Remove the TB from the car. Remove the MAF sensor from the TB. Put it in a safe place (they can be very delicate).

Use intake-safe spray cleaner (not carb cleaner) and a toothbrush. The back side of the TB is what needs to be cleaned. Spraying it in the front side will typically do nothing.

My 99 does the EXACT same thing. I posted this question once. Read what everyone had to say:

http://www.bonnevilleclub.com/forum/...&highlight=rpm

There are 100 or more reasons for a rough idle. Getting down to the detailed descriptions is what will get this fixed.

Everything that I've read and people that I've talked to say that this is common. It'* been doing it since 30,000 miles (when I bought the car) and I'm yet to get a check engine light out of it. Everything appears to be fine....

Thanks for the heads up on the carb spray.
I'll be sure to check out the other posts on the same idle problem.
I guess sometimes will these complex cars you just have to grin and bear it.

vita49
I read you previous post link about, Its amazing my series two does the
exact same think. You describe my problem to the tee, even the outside
temperature it does it at.
Did ya ever fix it? Or just live with it?
Funny I mentioned it to a dealer drivability guy and he just seemed to shrug it off!

I never did fix it. I talked to a GM mechanic also and he couldn't provide any insight and said it'* typical. I'm sure as you read in the thread that I started, everyone on here said it'* normal too. So, I've just learned to live with it. I still find it very interesting how it will run forever at 1500 RPMs until you rap on the gas. I've NEVER seen a fuel injected engine do that until I bought the Series II. Go figure!!

Interesting, we have come to the age of fuel injection with electronically
controlled engine management and we have to kick our cars down like
the old carburator cars.
I wonder if they have any secret service bulletins on this problem.
Do we have any dealership people on the board?

Rat...where are you??

Check out this link on an idle problem I found.
An ASE tech comments.
http://www.automotiveforums.com/vbul...d.php?t=188103