2007 Chevy Tahoe LTZ 5.3 L Idles rough but runs ok

SOURCE: when cold, it idles rough, revs high then low! After warmed up it runs fine

if it runs high when you first start it then mellows out,, theirs no problem , all of our chevys do that.... but if its sputtering or you hear a quiet popping noise check spark plugs

SOURCE: 1989 honda prelude enigne idles high then low irratic

I had the same problem on a Rover. There was a leak in inlet manifold that was caussing the problem.
To verify, spray some sealant to temporarily seal the inlet manifold .and the eratic idling should disappear for some time.
If it does, you know there is leak in inlet manifold which you can take of and refit with a new gasket.

Marvin

• 85242 Answers
• Posted on Feb 18, 2009

SOURCE: ROugh idle

there are 2 things that usually cause this, one is a dirty intake idle control valve and the other is hard engine mounts, I would say that both most likely apply to your car. try cleaning the intake with the following procedure from Ford.
Here is the most common cause of surges and stalls and low idle rough idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

SOURCE: 2002 chevy trailblazer has rough idle

it could be an o2 sensor. it could also just need a tune up

Ryan Lutton

• 1267 Answers
• Posted on Nov 22, 2010

SOURCE: 2004 Chevy Trailblazer idles rough.

If it has not pulled any codes (idiot light). Clean your throttle body, and change your spark plugs with A/C Delcos #41-103, most other brands will cause rough idle like Autolites and Bosch. This would be a cheap way to fix this problem.

If by chance you have just recently changed the battery or had the battery unhooked. Let me know, it's an easier fix that costs virtually nothing.