i have an 350 vortec with tbi. headers and dual exhaust . under accel cold it hesitates and runs rough . when its warm it runs awsome . any clues on how to fix the cold running prob ? please help. i installed a heated o2 sensor too

Kevin

its also in a 89 rs

Sounds like it is time to get into the ECM and do some tuning. The DIY PROM board on this site is a great resource. Did you happen to change the injectors over to the larger 350 engine injectors from the 305 injectors?

RBob.

its has 350 injectors . not sure on what to do with the ecm? let me know what ya think

Kevin

Kevin, your running a custom chip or a tuned eprom chip right?

where can i get a custom chip??????