Yesterday morning a mile from my house when I came to a stop light, I noticed the idle slightly bounching. I assumed a small vacuum leak. *boost gauge is not in car right now. I popped the hood and checked around, saw no loose vacuum hoses. I made sure the hose to the MAP sensor was tight. This morning I get to the stop light and again.. the idle fluctuates.. but get this - as the car warms up, the fluctuation stops!
It seems to only happen while the engine is still cold. It seems to stop after 3 miles. What could it be? Coolant problem?

 

Ill add that Ive been working on stereo stuff for the past 2 days. Could a weak alternator or low battery have anything to do with the idle?

 

I had that problem for a while, in my case it was because the hose to the MAP sensor wasnt a very tight fit. I put a nylon zip tie on it and the problem went away. Mine was so bad that I would start it and the idle fluctuation would kill the engine after about 5 seconds. Then it would slowly get better until fully warmed up when the idle would be perfectly smooth. You said the hose was tight though, hmmm.

 

Yeah, I even put a zip tie on the MAP sensor hose.
Ill drive it around somemore to see if anything changes now that its 65'degrees outside.

 

It sounds like the thermo wax valve. It is located by the throttle body elbow. It is a valve the lowers the idle after the car starts to warm up. Once the valve goes bad
it sticks and your idle goes to crap until the car gets real hot. It isnt expensive but it is a dealer part. If you have a small 90 degree philips you dont even need to take off the elbow to change it. Others speak up. I would put my money on it

 

hmm, Ill try and check it out and if the symptoms continue Ill fork over $ for the part. thanks for the insight.
Ill post my findings when I do finally solve this. any other ideas?