RPMs bouncing problem.

[FastPAt]

I didn't wanna look for a good reputable Chevy Colorado forum to just ask this one simple question, so might as well give it a shot here.

Basics:

It's a 5Cyl, has about 120,000kms, Automatic, RWD, has cruise, and T/C.

The problem, when I start to slow down and get down to under 2000Rpms, and come to a stop the RPMs will bounce up and down to about 1200 down to almost stall, and in some cases it WILL bounce down so far, that it will stall the engine, or tun it off, and I need to put it into park and start it again.

The check engine light has no come on, and no other problems seem to have come. Any thoughts?

[1991HCR32]

well if it was a skyline doing that #1 suspect would be cas maybe the newer chevys have tactometer aswell in the cas

[Snake556]

That's strange :S I've got the same truck as you (talked to you about it at Skymeet) and I haven't noticed anything like that. But if it's bouncing to the point of stall, I'd definitely bring it into a garage to at LEAST get checked out. That's not good at all.

[FastPAt]

Just a lil update. Well turned out it was the throttle body .... just a little bit of build up caused this, how? I have no idea there wasn't much to begin with but I just used a little cleaner and it came right off and the RPMs stopped bouncing.
Also Snake, check out your third brake light and make sure the seal around it is ok, apparently on the colorado's from 04 - 08 the seals start to sag and get old and water will seep down into the cab onto the floor. Happened to me on a heavy rainfall the other day and it soaked my drivers side floor, so I just put a little silicone sealer around it and it's fine now.

[Snake556]

Glad ya got it fixed, mano! And thanks for the tip! I'll definitely give that a look in the morning!