1991 Camaro RS L03 305. Falls flat on wide open throttle & during acceleration, you can definitely feel the dead spots while cruising. Picks right up after the dead spot on WOT and runs great. Vacuum is good, sensors are good. EGR by chance?

 

EGR valves have always caused me headaches as the TBI/TPI cars age. I got a 454tbi truck two years ago that I've been redoing. chased an off idle stumble issue for a while, verified all sensors were good. all the standard EGR "tests" suggested my egr valve was fine, it held vacuum and the diaphragm moved freely. I couldn't find a replacement for my specific EGR valve so I made a block off plate and the problem completely went away. I then had it tuned out of the prom. You can get/make a block off plate and put it on just to see if the EGR is the cause, then either replace it or have it tuned out.

 

Hard to say if base timing is off , tps has a bad spot or low fuel pressure. Thing to check.

 

Throwing a cap & rotor and plugs at it for giggles. Cap and rotor was corroded something awful, EGR and timing will be a definite check to factor in. Appreciate the feedback, I’ll jump back if it doesn’t line out.