Strange Cold start behavior

[patcal]

My 94 started doing something odd. When cold only, it will start normal, then the idle will go up to about 1500-200rpm, then drop to almost stalling about 500rpm. If I give it a little gas it will be OK. It settles down within a minute or less & idles normal. If I start it up warm, it seems normal. I ran some seafoam through the IAC about 2 months ago. It was sometime after that, the problem started. No codes, mileage seems good (22mpg). Any thoughts?

Pat

[Legacy777]

My Legacy did something similar to this years ago and I could never figure out what specifically was the cause of the problem. It could be related to a coolant temp sensor being lazy. Do you know if it's been replaced before?

[patcal]

Josh,

I have no history on the car. I bought it in March with 252K & nothing else. Since it's only about $20 I may just go ahead & change it.

Pat

[Legacy777]

Yeah, I think that's a good plan.