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Discussion Starter #1
03 envoy problem so when I go wide open (stomp on the gas pedal) seems to go to 3000rpms and doesn't really go any faster kinda seems to go slower but if I barely push the gas down I can actually get up too 60+mph but seems to take a bit it almost seems like if you were to max the weight on a car and then pull whatever it is that maxed it out , up a hill just seems to rev if you do find out what this is would u plz let me know I have spent atleast 300+ just in parts in this thing , and that's just for only this week not Including what I've spent in the past weeks , I've bee.trying 2 figure out what is going on 4 months now , so far I have replaced the variable valve timing solenoid twice , crankshaft position sensor 2 , pulled the throttle body and cleaned it , still hasn't resolved this issue I have replaced the spark plugs with the iridium plugs , it has 260k+ miles on it plz any help would be greatly appreciated I've been trying to figure this out so my wife and kids bought me a code reader that allows you to read codes and also does everything in real time plz let me know what 2 look for on or to check in real time on my code reader , thank you for everyone that responds or any help
 

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The first thing I would do is purchase a Haynes Manual for your Envoy. The second thing i would do is to scan your Envoy and see what the current, pending and history codes are, and the third thing I would do is to look the codes up in the Haynes manual.

What you are looking for are codes like P0300 through P0306 (P0300 is the code for an unspecified misfire while P0301 - P0306 are misfires for a specific cylinder). You'll also want to check for any codes indicating lean or rich fuel trims (P0170 to P0175).

Another really needed piece of test gear needed to sort this problem out would be a fuel injection pressure test gauge to make sure the fuel pump is strong enough (~50 psi). If the fuel pump is weak, then it too can cause problems like you describe.

Good luck!
 

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If you are experiencing the 3000 RPM limit while in park or neutral, that is normal. The PCM limits RPMs to prevent over reving. If this is occurring under normal driving conditions, I would suspect a clogged catalytic converter. An easy test would be to remove the O2 sensor on the exhaust manifold and see if that makes things better (this will reduce back pressure).
 

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Several things things come to kind.... but not in any real order..... here goes....

These points, made by you, bother me a lot:
  1. "wide open " & "3000rpms and doesn't really go any faster"
  2. "up a hill just seems to rev "
Not in any particular order - I say this is something to consider:
  1. Plugged catalytic converter
  2. Low fuel pump pressure/flow
  3. Retarded cam(s)
  4. Knock Sensor detects too much engine noise and is retarding ignition
  5. Torque convertor has lost some fins or the sprag is rolled over (I'm gonna take this as my first choice though)
Doing this other stuff is counter-intuitive: "I have replaced the ...." (reading from your list):
  1. variable valve timing solenoid twice
  2. crankshaft position sensor 2 ,
  3. pulled the throttle body and cleaned it ,
  4. I have replaced the spark plugs with the iridium plugs
All this is just a waste of money and I know that you now know it didn't solve anything either .... but it did lighten your wallet and cause you a lot of grief.

What you need is to DIAGNOSE... THEN REPAIR OR REPLACE AS INDICATED.

Throwing money and time at a problem just makes people angry, spends a lot of their money and creates a lot of hate toward a vehicle that cannot respond to your misguided, but good intentions.

You're doing what a lot of dealerships do - they go to the shelf and try a part that might work. When it doesn't improve on the situation, it still stays on the vehicle ... and on your bill ... and they go on to another shelf and the next part they can find that might work.

It bothers me that you're damaging your future with a vehicle that you really need some technical help with and you're gonna set it on fire as a burnt offering when you find ... that after a LOT of money - it still does the same things.

Check the ATF and tell us what condition it is in - smell, look and color... perhaps a small taste too - I did it for years and it never bothered ME!.
 

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Discussion Starter #5
Several things things come to kind.... but not in any real order..... here goes....

These points, made by you, bother me a lot:
  1. "wide open " & "3000rpms and doesn't really go any faster"
  2. "up a hill just seems to rev "
Not in any particular order - I say this is something to consider:
  1. Plugged catalytic converter
  2. Low fuel pump pressure/flow
  3. Retarded cam(s)
  4. Knock Sensor detects too much engine noise and is retarding ignition
  5. Torque convertor has lost some fins or the sprag is rolled over (I'm gonna take this as my first choice though)
Doing this other stuff is counter-intuitive: "I have replaced the ...." (reading from your list):
  1. variable valve timing solenoid twice
  2. crankshaft position sensor 2 ,
  3. pulled the throttle body and cleaned it ,
  4. I have replaced the spark plugs with the iridium plugs
All this is just a waste of money and I know that you now know it didn't solve anything either .... but it did lighten your wallet and cause you a lot of grief.

What you need is to DIAGNOSE... THEN REPAIR OR REPLACE AS INDICATED.

Throwing money and time at a problem just makes people angry, spends a lot of their money and creates a lot of hate toward a vehicle that cannot respond to your misguided, but good intentions.

You're doing what a lot of dealerships do - they go to the shelf and try a part that might work. When it doesn't improve on the situation, it still stays on the vehicle ... and on your bill ... and they go on to another shelf and the next part they can find that might work.

It bothers me that you're damaging your future with a vehicle that you really need some technical help with and you're gonna set it on fire as a burnt offering when you find ... that after a LOT of money - it still does the same things.

Check the ATF and tell us what condition it is in - smell, look and color... perhaps a small taste too - I did it for years and it never bothered ME!.
Atf fluid is red color , normal atf smell and is full , but the reason why I kept replacing the cam and valve timing solenoid , i kept getting that code even after all codes were cleared , but i took out the 02 sensor just to check rather it would run better or not and still seems to run the same I wish I could put a video on here to let everyone see what it is doing but got a code reader so I'm gonna see what the codes are
 

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Discussion Starter #6
If you are experiencing the 3000 RPM limit while in park or neutral, that is normal. The PCM limits RPMs to prevent over reving. If this is occurring under normal driving conditions, I would suspect a clogged catalytic converter. An easy test would be to remove the O2 sensor on the exhaust manifold and see if that makes things better (this will reduce back pressure).
I have just tried the 02 sensor trick and it still seems to run the same , what about the down stream 02 sensor is it the same way or do I just need to do this to both and then test it , but this is happening in drive so when I try to merge on the interstate , literally I have to let off the gas probably 25% throttle just to gain speed and sometimes it won't even do that , seems to just rev to 3000rpm and stays till I let up on the accelerator then seems to shift gear then it goes has no problem at what seems to be low rpms but definitely doesn't like high rpms but I have a code reader going to read them and will let you know what it reads but I am going to have the back pressure tested tomorrow also will let you know . Oh and jw if it was the cat would u not smell a rotten egg smell , now I have ran seafoam through the gas tank and crankcase and threw the intake vacuum line on the throttle body
 

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Discussion Starter #7
The first thing I would do is purchase a Haynes Manual for your Envoy. The second thing i would do is to scan your Envoy and see what the current, pending and history codes are, and the third thing I would do is to look the codes up in the Haynes manual.

What you are looking for are codes like P0300 through P0306 (P0300 is the code for an unspecified misfire while P0301 - P0306 are misfires for a specific cylinder). You'll also want to check for any codes indicating lean or rich fuel trims (P0170 to P0175).

Another really needed piece of test gear needed to sort this problem out would be a fuel injection pressure test gauge to make sure the fuel pump is strong enough (~50 psi). If the fuel pump is weak, then it too can cause problems like you describe.

Good luck!
Oh yes the book that was one of the first things I bought when I got my envoy , I have a scanner now it also let's me view real time information (while driving ) such as 02 voltage , fuel trim , air temp etc and also I am going to rent 1 of those fuel pressure tester from advanced auto, a long with the back pressure tester hopefully this tells me something tomorrow , I really wish I could record a video and upload it showing what is going on
 

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OK on having the book. Magnificent first step! If there was a blockage in the catalytic converter, the engine would run much better with the upstream O2 sensor removed. No need to remove the downstream O2 sensor.

Before you start collecting data with your code reader, put the upstream back in and hook it up. That way you can collect all the pertinent data as you drive.

Regarding fuel trim values, the long term fuel trim (LTFT) values are more important relative to the short term fuel trim (STFT) values. Short term values and the upstream O2 sensor voltages can and do bounce around all over the place. STFT values in the range of -10% to +10% are considered normal. Same for LTFT values. Long term values can change, but they do not change as rapidly as the STFT values.

Here is a link to a webpage that does a decent job of explaining fuel trim values and how to interpret them:


You might also want to see if you can monitor misfire counts for each cylinder using the diagnostic scanner you have. Misfire counts are very helpful when tracking down a P0300 code.

Just remember to write down all the OBD 2 codes that your scanner shows before you erase them.

Good luck!
 

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Discussion Starter #9
OK on having the book. Magnificent first step! If there was a blockage in the catalytic converter, the engine would run much better with the upstream O2 sensor removed. No need to remove the downstream O2 sensor.

Before you start collecting data with your code reader, put the upstream back in and hook it up. That way you can collect all the pertinent data as you drive.

Regarding fuel trim values, the long term fuel trim (LTFT) values are more important relative to the short term fuel trim (STFT) values. Short term values and the upstream O2 sensor voltages can and do bounce around all over the place. STFT values in the range of -10% to +10% are considered normal. Same for LTFT values. Long term values can change, but they do not change as rapidly as the STFT values.

Here is a link to a webpage that does a decent job of explaining fuel trim values and how to interpret them:


You might also want to see if you can monitor misfire counts for each cylinder using the diagnostic scanner you have. Misfire counts are very helpful when tracking down a P0300 code.

Just remember to write down all the OBD 2 codes that your scanner shows before you erase them.

Good luck!
Alright so I have my innova car scan advisor + repair solutions 2 hooked in and the reader is yet again telling me P1345 crankshaft position (CKP) - Camshaft position (CMP) Correlation but ok so this code reader hooks up too my computer and my phone and it also gives the codes on my phone which in return stores to my phone but it also gives me a P0340 (STORED) Camshaft position sensor A circuit ( Bank 1 or single sensor ) and I guess from were I unplugged it P0130 (PENDING) 02 circuit ( bank 1, sensor 1 ) , P0135 (PENDING) 02 Heater Circuit ( Bank 1 , Sensor 1 ) in total there r 4 codes showing
 

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So I have 4 codes showing P1345 (STORED) Crankshaft position (CKP) - Camshaft Position (CMP) Correlation code # 2 P0340 (STORED) Camshaft Position sensor A circuit ( Bank 1 or single sensor ) code 3 P0130 (PENDING) 02 circuit ( bank 1 sensor 1) code 4 P0135 (PENDING) 02 Heater Circuit (Bank 1, Sensor 1 )
 

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(climbing 'way out on a limb here....) I'd take on the CKP first.

A lot of the other device/sensor codes depend on an accurate, solid CKP signal and they are possibly complaining that they cannot follow the bogus info from the CKP.

This is just MY opinion.... but it's a logic tree I'd use --- look for the biggest common denominator!
 

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Addendum ---> your "P0135 (PENDING) 02 Heater Circuit (Bank 1, Sensor 1 ) " isn't a good thing either

This usually means the O2 heater is either burnt out or is disconnected somewhere along the power circuit - and possibly it's ground circuit which is one of the two black wires.

Actually both black wires are supposed to be the same ground although they may not go to the same place for a ground - it's just that GM wants a dedicated ground for both the heater and the sensor.
  • IIRC----> the O2 sensor ground is back at the ECM whilst the heater may be to a chassis ground ---- but because the ECM will detect the loss of voltage/current going out to the O2 sensor it will shoot up a Boolean Flag - which is what a PENDING CODE is all about.
 

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Also, check your camshaft position sensor and make sure that the connector to it is properly seated and making good electrical contact. Something is wrong there according to the P0340 code. If the camshaft position sensor is not operating properly, then the data it is or is not providing will not jive with the information from the Crankshaft sensor and hence set a P1345 code.

If after you correct the cause of the P0340 code, and you have cleared the other codes using your code scanner, and the P1345 returns, then you likely have a problem somewhere in the crankshaft position sensor circuit. IF it turns out you have a defective crankshaft position sensor, a crankshaft position sensor learning procedure MUST be performed.

Regarding the O2 sensor codes, did you reinstall the O2 sensor before you read the codes? Either way, I would use the code reader and clear the codes, and then drive around and see what codes come back. If you get the same codes (assuming you have not repaired the causes of the P01345 and P0340 codes), I agree with Ravalli Surfer about there being something wrong with the upstream O2 sensor - either a wiring problem or a defective sensor.

I also agree with Ravalli Surfer on the other sensors depending on accurate, reliable information from the crankshaft sensor.

Good luck!
 

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Addendum ---> your "P0135 (PENDING) 02 Heater Circuit (Bank 1, Sensor 1 ) " isn't a good thing either

This usually means the O2 heater is either burnt out or is disconnected somewhere along the power circuit - and possibly it's ground circuit which is one of the two black wires.

Actually both black wires are supposed to be the same ground although they may not go to the same place for a ground - it's just that GM wants a dedicated ground for both the heater and the sensor.
  • IIRC----> the O2 sensor ground is back at the ECM whilst the heater may be to a chassis ground ---- but because the ECM will detect the loss of voltage/current going out to the O2 sensor it will shoot up a Boolean Flag - which is what a PENDING CODE is all about.
Alright
(climbing 'way out on a limb here....) I'd take on the CKP first.

A lot of the other device/sensor codes depend on an accurate, solid CKP signal and they are possibly complaining that they cannot follow the bogus info from the CKP.

This is just MY opinion.... but it's a logic tree I'd use --- look for the biggest common denominator!
Alright here comes a dumbass question what is a CKP and how can I test that , also so I just find the two black wires coming from the upstream 02 wiring and make sure they have a good ground or should I make a new ground and connect both to 1 ground
 

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Also, check your camshaft position sensor and make sure that the connector to it is properly seated and making good electrical contact. Something is wrong there according to the P0340 code. If the camshaft position sensor is not operating properly, then the data it is or is not providing will not jive with the information from the Crankshaft sensor and hence set a P1345 code.

If after you correct the cause of the P0340 code, and you have cleared the other codes using your code scanner, and the P1345 returns, then you likely have a problem somewhere in the crankshaft position sensor circuit. IF it turns out you have a defective crankshaft position sensor, a crankshaft position sensor learning procedure MUST be performed.

Regarding the O2 sensor codes, did you reinstall the O2 sensor before you read the codes? Either way, I would use the code reader and clear the codes, and then drive around and see what codes come back. If you get the same codes (assuming you have not repaired the causes of the P01345 and P0340 codes), I agree with Ravalli Surfer about there being something wrong with the upstream O2 sensor - either a wiring problem or a defective sensor.

I also agree with Ravalli Surfer on the other sensors depending on accurate, reliable information from the crankshaft sensor.

Good luck!
I have actually replaced the crankshaft position sensor twice but the one they gave me at the auto zone parts store I promise looks a bit bigger
 

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I have actually replaced the crankshaft position sensor twice but the one they gave me at the auto zone parts store I promise looks a bit bigger
The relearning process that has got to be the culprit so on the factory one I got this code along with the vvt so replaced both with brand new and then it came on again s ok I figured it has to be a defective part so took it back and now this is the third time and still showing me this code but like I was saying before my code reader hooks to my phone and tells me what the code is and how to fix , and where to even get the part and it keeps telling the vvt solenoid again and now a sprocket look almost like a gear on a mountain bike but comes with a tensioner bolt
 

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Regarding your first question. The CKP sensor is the Crankshaft Position Sensor and it is located on the drivers side of the engine block just before the bell housing and above the #2 knock sensor. Google "2003 Envoy 4.2L crankshaft position sensor location" and a number of diagrams will come up. Here is a link to an article on how to test a CKP sensor - How to Test a Crankshaft Position Sensor | 1A Auto

Also, if you do replace the crankshaft position sensor, you'll need to do a crankshaft position sensor relearn procedure. I would not replace it just for the heck of it or just in case.

Regarding the 2 black wires from the oxygen sensor Ravalli was referring to, I'll let him answer that. In the meantime, I did find an article on how to diagnose O2 sensor heated circuit failures. Here is the link - Diagnosing O2 Sensor Heater Circuit Failures | MOTOR

OK on the Autozone camshaft sensor looking bigger. 2 questions, Does it fit into the hole for the camshaft sensor, and does the electrical connector fit securely? If not, they did not give you the correct one. The ACDelco part number for the camshaft position sensor is 213-1557. When I had to replace mine, I used a BWD CSS1579 camshaft position sensor that I got from Advance Auto Parts and it worked just fine. It also looked identical to the factory sensor.

Good luck!
 
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