Hey guys Just bought my Iroc loved the cars since i was a kid and my father had one but I'm having as issue. The car has been sitting for 4 years but runs great. The only problem is whenever the car warms up and has been ran for a while when you step on the gas it putts along and there is no acceleration. even when the car isn't warmed up you notice a lack of acceleration. now i replaced the throttle positioning sensor and the mass airflow sensor and also there are no codes the light is off. i would really appreciate some help id love to get on the road and start driving!

 

Sounds fuel-related.

Check the fuel pressure WHILE IT'S IN THE ACT OF SCREWING UP. That means, NOT while sitting in the driveway idling; you need fuel pressure readings while driving, WHILE IT'S IN THE ACT of stumbling etc. Try taping your FP gauge to the windshield.

Might wanna just change the fuel filter, especially if you haven't lately, and see if it changes anything. Never hurts to catch up on the usual "deferred maintenance" (aka "neglect") even if it's not the cure for "The Problem" of the minute.

 

if it lacks acceleration all the time it sounds like a timing issue. have you tried checking that?