Rough idle issue

[alvocado]

The idle on my '02 Yukon Denali has been a bit rough lately. I can feel a slight sputter at idle RPM of 500. The truck has 57k miles and I had the TBI cleaned at 32k after the truck pulsated at idle (the RPM bounced between 500-700 RPM). The pulsation was pretty severe compared to the current problem.

 

Is this a sign of more carbon buildup on the TBI, worn plugs (even though they should last 100k) or something else? Any help on troubleshooting would be great so I don't replace parts unnecessarily. Thanks!

[GM-Tech]

I'd start by cleaning the throttle body. It certainly can get enough buildup in the 25,000 miles that it's been since the last time you had it cleaned and could be the problem. It's easy enough to do, so why why go looking for bigger problems first.

[alvocado]

I'd start by cleaning the throttle body.  It certainly can get enough buildup in the 25,000 miles that it's been since the last time you had it cleaned and could be the problem.  It's easy enough to do, so why why go looking for bigger problems first.

 

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I'm all for the easy approach. This may be a naive question but do I need to remove it and replace the gasket or can it be cleaned in place?

[GM-Tech]

I'm all for the easy approach.  This may be a naive question but do I need to remove it and replace the gasket or can it be cleaned in place?

 

In place. Electronic throttle controls should not have anything sprayed in them though. Soak a rag, hold the throttle plate open and use that to wipe out the throttle body.