another sr20 with horrible idle.. HELP!

[Slide-or-Die69]

Hey, I gotta 89 240 with a redtop in it. It's always had a boost leak I think because at full boost when it's cold it would pop and backfire real bad but not as much when it's warm. Lately I just changed the intake manifold and cleaned out the iac with carb cleaner and brake clean. After it all went back on I noticed a very rough idle. It goes from 1k - 2k very fast and slows down a bit when it warms up. I adjusted spark timing but that didnt help it so much , it seemed like it came back after like 20 seconds. I'm not sure if its a vaccuum leak or what but my gauge reads 15- 20 hg. The maf is regrounded on a valve cover bolt but i dont think thats a problem. Oh yea and i changed a couple vaccuum lines and they had oil or something that looked like it in there and was coated on the whole inside. I sprayed the carb cleaner in the iac valve maybe thats it? idk Any help would be awesome. Thanks