The Nissan Path

Hey guys, I have a quick question about my 1990 SE. After replacing my timing belt (I actually made a pretty good youtube video about it, here: http://www.youtube.com/watch?v=Uk_oMHRRh7Y), dist cap and rotor, spark plugs, thermostat, I noticed that my idle was kind of rough. It will drop and surge between 900-600 rpms, and occasionally die completely if I put it into reverse too quickly after a cold start. With the AC on however, idle is perfectly smooth and straight, 900rpms (warmed up). At first I thought I might have skipped a tooth while aligning the timing belt but the truck pulls strong and doesn't bog, so then I cleaned my MAF and the connections, still no change. Since the TB change I have driven it about 1000 miles, condition does not get better or worse. I'm not sure where to go from here, any suggestions?

Thanks