2001 slight surging when cold

[markdunn99]

2001 2.2L - 78K miles....I've noticed when first starting cold...engine RPM seems higher than I would expect it to be - is revving fairly high.....but does come down to normal after a bit...and car seems to take longer than I would expect for temp to come up to normal....if I take off while temp gauge is still in the cold range...the engine seems to surge up and down somewhat...not to any great extent that it is affecting the operation of the car...but enough so you can feel that something is going on...then once temp gauge reaches normal...no problem. Any thoughts on this? Coolant Temp sensor perhaps? They're cheap so I might just throw a new one in and see what happens. Also figured I'd give the IAC a good cleaning. Thanks for any thoughts.

[Mister_Perkins]

I would start with the IAC . You have the right suspicion as to what the problem may be linked to. You may also want to check for vacuum leaks. That would cause your car to idle a little higher too. Vacuum leaks can be linked to hoses, where the intake manifold connects to the head, leaky injectors (Bad o-rings). Since after it warms up it idles correctly I would first try the IAC cleaning

[markdunn99]

What's normal idle RPM when cold? I looked at it this morning...guess it was idling around 1700-1800 rpm when cold....so maybe that's not abnormal anyway and I'm just imaging it. It just seems higher than I'm used to with other cars I've driven....and even if driving off when still "cold" I don't recall other cars having this sort of "surging" feel until it warms up. Perhaps it's nothing....maybe I'll have a look at the IAC this weekend and give it a good cleaning...couldn't hurt. Where's it located on this car? 2001 2.2L... Thanks

[fenixus]

1,800rpm after cold start (with ambient close to 30-40F) is normal. that speed should gradually drop over time as engine gets warmer.

if you want, you can spray (e.g. with Sea Foam Deep Creep) and clean IAC hole with a tooth brush, look here, it's very easy:
How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures