We just finished an sr20 black top swap on my 89 240. After we cranked up the car it was runing really nice and smooth. About 5 min later it started idling weird. We have checked the vacum lines and the all the sensor. Everything seems to be working fine. Any one has an info why I'm having this problem? Thank in advance.

 

boost leak

 

boost leak or bad MAF,,,, been tere done that. easy to over look. rev it up to 2500rpm anything after that it wont run worth a ****....bad MAF

 

have you tried just driving it around, pretty much the same thing happend to me, i started it up black nastys came out the exhaust, everyday the idle got better, and then i ran fuel injector cleaner in it and it helped.