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2003 chevy trailblazer_lt
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26 Posts
Discussion Starter #1 (Edited)
Haven't been on here in a looong time, but I am having an issue with my 2003 TrailBlazer with the I6 engine.

A couple of days ago, it seemed as if it was having some power loss while accelerating. Just to confirm, I floored it and it accelerated kind of slower than normal. The acceleration began slowing up a good bit around 4000 rpms and continually dropped off in acceleration until it hit about 5400 rpms and just stayed there. No shifting or accelerating further until I let off the gas pedal for a moment. Then it threw the codes P0300 and P0442. Those are the only things to show up on the dash, no other warning lights of any kind. It works just fine with some small power loss below 3k rpm, but if I run into a big hill or something, it's having trouble getting up. It feels smooth while accelerating too, so I don't think it is actually a cylinder misfire.

The vehicle has 110k miles on it. Already changed out the spark plugs to AC Delco iridium at 90k-ish, just replaced the transmission fluid and cleaned out all of the intake and throttle body, just had the fuel filter replaced because I thought that might be gunked up and it's not letting enough fuel through at higher rpms, plus I noticed the issue right after filling up at a Sunoco. Maybe just bad gas, but I doubt that would cause this bad of acceleration.

Still having the problems though... I'm thinking torque converter or catalytic issue. Anyone else have this issue or know of a fix?
 

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2006 saab 9_7x
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450 Posts
PO300 is random misfire and PO442 is Evaporative Control problem. Does the transmission feel like it is slipping? Take it to a tranny shop and have them diagnose for problems.
 

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2005 chevy trailblazer_ls_ext
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7 Posts
P0300 can be a pain to track down as well as a P0420. Search from common P0420 fixes and start there. It is a vacuum leak of some sort. As for the shifting many things can cause a transmission to act up if the engine is acting up.
For now I would really stay away from flooring it.

When is the last time you did a tune up?
 

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2003 chevy trailblazer_lt
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26 Posts
Discussion Starter #5 (Edited)
No, transmission isn't slipping. Engine revs like normal (smooth and all) but the vehicle is a little sluggish until the RPMs go above 4000 and then it just slowly drops off in power until it isn't accelerating anymore. Just had the trans fluid replaced.

It's sitting at the dealers where we bought it so they can diagnose for now. Only floored it the one time on my drive to visit my parents to see if it was really having power loss when it felt a little sluggish, haven't done it since. Driving my parent's Suburban for now so I could get back to work. Just had all the throttle, intake, and all of that stuff cleaned out. I'm thinking the cats are clogged, which I would think explain both codes and vehicle maxing out before shifting, but open to all other suggestions.
 

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2003 chevy trailblazer_lt
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7 Posts
I'm having identical issues. P0300. I've replaced fan clutch, crank n cam sensors, upstream o2, thermostat 3x, and ect.
Any feed back from the dealer?
My dealer wanted $700 to change the IPC. Somehow I don't believe the instrument panel is the issue
 

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2004 gmc envoy_slt_xl
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7 Posts
Similar Emissions MIL on My '04

When I had the P04XX codes, my plastic gas tank was cracked. It was a Service Bulletin and GM had a "special recall" on the affected models in a certain range of VIN. If you have less than 150K, and is within the VIN range, you can get it replaced free at your local dealership. I was having EVAP errors and couldn't figure it out and $800 of diagnostics later, it was a service bulletin found by the mechanic. Hope you figure it out!
 

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2003 chevy trailblazer_lt
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26 Posts
Discussion Starter #8 (Edited)
Sorry for the delay. The dealer said it was a transmission issue and performed all these tests. They wanted $5k for replacing the trans. On a vehicle worth maybe $4k? Yeah right! Took it to a specialized trans place that has been in business for 55 years so they must be doing something right and they called BS on that, no trans problem at all. They sent me to their trusted people at an engine place and turns out the catalytic converter had collapsed inside and was blocked up a good bit. Replaced that and it works fine now... Now to contact the original dealer who said they tested the cats and exhaust and they were fine and demand my money back.
 

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2004 gmc envoy_slt_xl
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7 Posts
Glad you got fixed

I was having the identical issue and I was ALSO told it was my transmission!!! People don't care any more. Hang parts, make money instead of actually doing some work and FIXING or FINDING the real issue. Good luck!!!
 

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2003 chevy trailblazer_lt
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26 Posts
Discussion Starter #10
Some people just want to make money any way they can. I'm sorry, but if you tell me it's the transmission when that doesn't seem right at all and replacing it doesn't fix the problem, then I'm going to think you are an idiot and you will never get my business again. And I will spread the word to my friends and family not to go to your dealership. People act like everyone is a chump these days.
 
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