Before everyone badgers me for not searching other posts, believe me I have. Ive found some useful info, but my circumstances are a little weird . I just did a Dohc Zc swap in my 91 HF CRX, went well except after the fact the transmission sucked. The engine drove and idled great. I then parked it and did a tranny swap. Left the engine in the car, swapped 'em out, dropped the car and drove it. Now my idle pulses from 800 - 1500 rpms when its warmed up. If it was a vacuum leak, wouldn't it doin it all the time? not just when the engine is warm? I dont get it, cuz it didnt do this before the tranny swap, and I didn't even touch the engine components in the swap, that I know of at least. So what's up? anybody got any ideas? Ive been postin about this car lot cuz most everybody on here knows their shit and you guys are helpin me a lot. So thanks in advance.