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Discussion Starter #1
Hi,
I have a 2004 Envoy XL with almost 168,000 miles on it and I recently started to have a few problem that I hope I can get help with.

1) When I start the Envoy it idles rough but it gets worse when I put it in drive. With it in drive I have my foot on the brake pedal and the idle is so bad that it want to stall which it did at a red light. It seems that after the engine warms up to 199 degrees it goes away.
2) The check gauge comes on and my oil pressure drops to 0 for a short time and then returns to 40. The oil is topped off.

Any help/suggestions would greatly be appreciated.

Thanks,
Joe
 

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2008 chevy trailblazer_lt
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72 Posts
With an electronic throttle body (if yours is like my 2008 version), I don't know if you can clean them while moving them manually, like you could with old school cable stuff. My plan is to remove mine and spray it inside and out a try not to get liquid into the electronics parts. Maybe someone can chime in about it. The first time I did one, I had the Mrs. giving it throttle to try to keep our HHR from dying, as I sprayed in cleaner with the motor running. The dealership wanted about $150 for this service so we did it ourselves back then.

Rob in AZ
 

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2003 gmc envoy_slt
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You can open it up manually while cleaning it, but I'd follow all the instructions on this forum (e.g., removing the solenoid, removing the TB from the engine, etc.).
I just did this on my '03 Envoy last summer when I was having a rough idle issue and it was super easy. I was surprised by the amount of gunk I cleaned off.


Don't forget to reset the PCM after cleaning the TB:


Reset the PCM
To reset the PCM, pull fuse #10 and #28 for 30-60 minutes. Replace the fuses, then turn the key to the run position for 2 minutes. Then turn the key off and start the truck and let it idle for 10 minutes with the AC off. Turn the ignition off. The PCM should now be reset.


Ultimately, my rough idle issue was a bad coil. Replacing that fixed the issue.
 
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