Still trying to learn everything there is about the H23 on my 93 Prelude Si. The car has about 141,000 miles on it & is completely stock besides an aftermarket ram-air intake and header.

I have a constant idle surge of 1k-2k RPMs whenever the car has been started after a long sit; just as if I was blipping the throttle. The surging will stop once the car has reached normal operating temperature. I'm guessing after something has had time to heat up, it just operates correctly.

Any ideas? Maybe something is clogged, EGR?

 

Mine used to do it and i think its a common problem(not really problem just nusence with preludes). Check your IACV. also look in the search under surging idle,etc. its been covered quite a lot.

 

sounds like your FITV to me.. look up FITV in search and you'll come up with a bunch of threads