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Discussion Starter · #1 ·
Hello! New here... Just got an 03 Trailblazer 4.2 with 212k miles on it with some sluggish acceleration. I need to replace the VVT solenoid (have it being delivered tomorrow) but I am not sure if that will still fix the issue. If I do replace the solenoid and its still sluggish, what are other issues that can cause this issue? Ive seen reports of like a clogged Cat Conv but I think it may be transmission related (such as the torque converter) because it has a hard time with hills and then also it has an issue changing gears... Any suggestions would be appreciated!!!
 

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Discussion Starter · #3 ·
Pressure test for a plugged cat first --- it's cheap and a slam-dunk easy test at almost any muffler shop.
When you say cheap, how much are we talking? Im working with my hubbys money rn while he's over seas so I need to know how much to ask him for the money
 

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Dirty engine oil can cause sluggishness as well.
Is the check engine light on? Does it work?
Simple items you can do yourself.

Do the simple stuff first:
Engine oil change. Use the correct oil - 10W30. 7quarts on the 4.2 inline 6 cylinder.
What does the inside of the oil filler cap look like?
Is transmission fluid up to the full line? Uses Dexron VI. Top it off. What does it look like?
Is the air filter totally plugged up or can you see sunshine through it? You'll need a screwdriver to get it out.
When was last time fuel filter was replaced? Google how to change it - no jack needed.

Then, like Ravalli says, have a muffler shop check for plugged cat. At 212K, that's a good bet, but what I've listed above are maintenance items which will need to be done regardless since we have no maintenance history on the vehicle.

DO NOT shoot the parts cannon willy-nilly or you may see lots of hubby's money go bye-bye.

Welcome to the Forum!
Don't be afraid to ask questions as none of us are mind readers!
 

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REEal
When you say cheap, how much are we talking? Im working with my hubbys money rn while he's over seas so I need to know how much to ask him for the money
Realistically .... $30 - $40 for the pressure test including the screw fitting.

Gauges won't even be necessary if it's bad enough to affect driveability.

Got a power drill?
Do the test yourself.
The fitting is cheap after the test to plug the hole up.
 

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Discussion Starter · #7 ·
Dirty engine oil can cause sluggishness as well.
Is the check engine light on? Does it work?
Simple items you can do yourself.

Do the simple stuff first:
Engine oil change. Use the correct oil - 10W30. 7quarts on the 4.2 inline 6 cylinder.
What does the inside of the oil filler cap look like?
Is transmission fluid up to the full line? Uses Dexron VI. Top it off. What does it look like?
Is the air filter totally plugged up or can you see sunshine through it? You'll need a screwdriver to get it out.
When was last time fuel filter was replaced? Google how to change it - no jack needed.

Then, like Ravalli says, have a muffler shop check for plugged cat. At 212K, that's a good bet, but what I've listed above are maintenance items which will need to be done regardless since we have no maintenance history on the vehicle.

DO NOT shoot the parts cannon willy-nilly or you may see lots of hubby's money go bye-bye.

Welcome to the Forum!
Don't be afraid to ask questions as none of us are mind readers!
Lots of great things here for me to check! I just did an oil change (though my oil filler cap said to use 5W-30/7qt)
The cap looked fine, wasnt cracked or disgusting... I did throw some Restore in the engine with the oil change to help with any compression issues
The trans fluid I havent checked yet but I will do that, I was thinking of taking it and having the fluid flushed and refilled since it does have 212k miles
Ill check the air filter now and get back to you and as for the fuel filter I have no idea cause I just got the vehicle on the 1st for a previous owner who beat the hell out of it...

I replaced the serpentine belt tensioner and the radiator fan clutch yesterday (was advised to do so by AAMCO) which definitely helped with performance but still sluggish. Ill get these things done and let you all know what I find out!
 

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Don't flush the transmission ... service it correctly by dropping the pan and then you can see inside to get a decent appraisal of it.

Tear the old filter apart to see what it's caught and clean the magnet to see how much ferrous material it caught too.

Those things won't be done by flushing. You dont need to replace all the fluid every time ... besides, I would never allow my customers to risk crippling their vehicle by flushing.

I've had overhauls created by other shops that did flushing. It's just risky on an older unit.

PS ... the reason why I recommend the drill-and-screw pressure test is because not many people have the special socket to remove an oxygen sensor without damaging it.

PPS ... don't take any advice from AAMCO. That's like going to a witch doctor for orthopedic surgery. Belts, hoses and a wax job won't fix performance issues.
 

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Discussion Starter · #9 ·
Don't flush the transmission ... service it correctly by dropping the pan and then you can see inside to get a decent appraisal of it.

Tear the old filter apart to see what it's caught and clean the magnet to see how much ferrous material it caught too.

Those things won't be done by flushing. You dont need to replace all the fluid every time ... besides, I would never allow my customers to risk crippling their vehicle by flushing.

I've had overhauls created by other shops that did flushing. It's just risky on an older unit.

PS ... the reason why I recommend the drill-and-screw pressure test is because not many people have the special socket to remove an oxygen sensor without damaging it.

PPS ... don't take any advice from AAMCO. That's like going to a witch doctor for orthopedic surgery. Belts, hoses and a wax job won't fix performance issues.
I mean I did do my own check at home once AAMCO gave me the advise to see how the parts were and they definitely needed to be replaced. The shaft for the fan clutch was cracked and splitting and the tensioner was weak (not horrible but definitely showed signs of low tension and risked belt slipping)... The VVT solenoid they said was completely dead and I had my brother confirm this hence why im replacing that as well... As for the transmission, Im not really comfortable doing any of that work myself because I know if I mess that up then thats gonna be an expensive screw up
 

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The VVT alone will drop power and performance .... repair the obvious and then let the chips fall.

Don't go poking the bear!

VVTs fail from rusting into a locked position; be sure to ask about that when you can.
 

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Don't flush the transmission ... service it correctly by dropping the pan and then you can see inside to get a decent appraisal of it.

Tear the old filter apart to see what it's caught and clean the magnet to see how much ferrous material it caught too.

Those things won't be done by flushing. You dont need to replace all the fluid every time ... besides, I would never allow my customers to risk crippling their vehicle by flushing.

I've had overhauls created by other shops that did flushing. It's just risky on an older unit.

PS ... the reason why I recommend the drill-and-screw pressure test is because not many people have the special socket to remove an oxygen sensor without damaging it.

PPS ... don't take any advice from AAMCO. That's like going to a witch doctor for orthopedic surgery. Belts, hoses and a wax job won't fix performance issues.
I couldn't disagree more on not flushing the transmission. I flush everything I own no matter the miles and have yet to kill one. Granted I don't do it to try and fix something, rather old, nasty, varnished fluid simply cannot perform as well as fresh fluid. I drop the pan, put a new filter in, and refill. Next I pop off the return line, shove a hose over it, and put that in a milk jug. Fire up the car and let the tranny do the pumping. Fill 3 gallon jugs and you're good and clean.

Also OP, was this thing ever not gutless? I'm wondering if when it's all 100% it won't be up to what you're expecting? They're not rocketships.
 

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Discussion Starter · #12 ·
I couldn't disagree more on not flushing the transmission. I flush everything I own no matter the miles and have yet to kill one. Granted I don't do it to try and fix something, rather old, nasty, varnished fluid simply cannot perform as well as fresh fluid. I drop the pan, put a new filter in, and refill. Next I pop off the return line, shove a hose over it, and put that in a milk jug. Fire up the car and let the tranny do the pumping. Fill 3 gallon jugs and you're good and clean.

Also OP, was this thing ever not gutless? I'm wondering if when it's all 100% it won't be up to what you're expecting? They're not rocketships.
Im honestly just trying to make it so the trailblazer can tow a small trailer from AZ to New Hampshire when my hubby gets out of the Marines... I replaced the VVT solenoid just now and im waiting for the codes to clear so I can drive it around the next couple days but some codes that did pop up were P0420 (Catalyst System Efficiency Below Threshold Bank 1) and P1345 (Electrical Short: Ignition Coil Output Stage 3) not including the P0014 ('B' Camshaft Position Timing Over-Advanced Or System Performance Bank 1) I am NOT getting any codes regarding the transmission which I am glad for, I just want to change the fluid because it has 212k miles on it
 

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If the trans is healthy absolutely flush it the way I described, it will buy you life in the long run. How big of a trailer do you want to tow? My sister had a 06ish 4.2 TB and I used it to tow Uhaul's biggest trailer from MI to CO. I kept it in 3rd gear the whole time and it was a champ the whole way, zero mods. The catalyst code may be a second order effect of the other stuff. If I were you, I'd swap #3's coil with another and see if the code stays or follows. If it follows, you know it's a junk coil.
 

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Discussion Starter · #14 ·
If the trans is healthy absolutely flush it the way I described, it will buy you life in the long run. How big of a trailer do you want to tow? My sister had a 06ish 4.2 TB and I used it to tow Uhaul's biggest trailer from MI to CO. I kept it in 3rd gear the whole time and it was a champ the whole way, zero mods. The catalyst code may be a second order effect of the other stuff. If I were you, I'd swap #3's coil with another and see if the code stays or follows. If it follows, you know it's a junk coil.
Good to know, ill give that a try... As it was I was thinking of replacing all the plugs and coils anyway cause no one replaces t hose until theyre bad... As for trailer size, we were wanting to get a 14x6 cargo to convert into a camper after the move and stuff... Nothing crazy
 

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Good to know, ill give that a try... As it was I was thinking of replacing all the plugs and coils anyway cause no one replaces t hose until theyre bad... As for trailer size, we were wanting to get a 14x6 cargo to convert into a camper after the move and stuff... Nothing crazy
I just looked and it was a 6x12 tandem axle that I hauled my sister's crap out here in (in her own car).

Wheel Tire Automotive parking light Automotive side marker light Car


Wood Asphalt Road surface Floor Plant


For the record, I made a single attempt to back that trailer to the house. Not that I'm bragging or anything. . .

I'd say a 14x6 won't give you any trouble. I've hauled bigger with out Envoy at altitude. Let us know how it goes.
 

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By all means ---- flush it!

That singular process bought me a 52 foot yacht in Dana Point.

Water Sky Boat Watercraft Naval architecture



Love it --- bad advice backed up by ONE anecdote.
 

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By all means ---- flush it!

That singular process bought me a 52 foot yacht in Dana Point.

View attachment 58812


Love it --- bad advice backed up by ONE anecdote.
Yes, because my single post pertains to a single vehicle let alone a single transmission type. Keep pushing 20 year old, nasty, broken down fluid on folks with otherwise healthy vehicles who'd actually benefit from a flush. Great way to make their vehicles last forever.
 

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Discussion Starter · #18 ·
Look, all I know is the transmission fluid is black and smells burnt... it needs to go period... As of right now, I cleared the codes and I will see what pops back up (if anything) in a couple days after driving it around and what not... Ill post again on saturday with what ever codes popped up and go from there
 

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Look, all I know is the transmission fluid is black and smells burnt... it needs to go period... As of right now, I cleared the codes and I will see what pops back up (if anything) in a couple days after driving it around and what not... Ill post again on saturday with what ever codes popped up and go from there
Regardless of your stance on the transmission fluid flush, cylinder 3 has something up so expect that to return.
 

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Discussion Starter · #20 ·
Regardless of your stance on the transmission fluid flush, cylinder 3 has something up so expect that to return.
Yeah I already priced the ignition coil from Rock Auto... will order it tomorrow after work... Also Ravalli, Its kind of hard to trust the advise from someone who suggested to drill a hole in my muffler/cat converter...
 
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