i have a 93 coupe(dx, i think) with a b18. the idle surges when the car is started from cold. it also seems that it revs up too high on a cold startup. i would estimate it starts up at close to 3000rpm, however i do not have a tach to verify that. after startup, it idles down to fast idle and then begins to surge up and down. as the car starts to warm up(but before full operating temp) the idle smooths out and stays.

i searched on here for a while, and almost all results said to clean the iacv and fitv. i went after the fitv first because it controls the fast idle and thats when my problem is occurring(at a cold start). i took it off, and it didn't look dirty like many of the pics that came up in my searches. i moved the plunger with my finger and it moved freely, so i bolted it back up. the car seemed to start a little better after that, but it was back to surging within a day or two.

i cleaned the iacv after that with no change. so, i took the fitv apart again and cleaned it thouroughly. at this point the idle began to surge when the car was fully warmed up. so, i swap iacv with my other civic and both cars run fine at first. shortly after, the surging was back, but the other car is still fine(never swapped the iacv's back). now, i am covinced that the fitv is bad, and i replace it with a new one from honda.

the result is that cold idle surge is still there, but the car is fine once warm.

i also checked for vacuum leaks and didn't find any.

any ideas?

btw, sorry for the long post, but it is driving me nuts and i wanted to be as descriptive as possible.