I've got an 87 Trans-AM that had a 305 TPI, but spun a bearing, so replaced with 350 Truck engine. Kept the TPI, changed to 28lb injectors, 350 TPI computer chip, and adjustable fuel press. regulator. Car has been running strong for several years, but several months ago developed a hesitation and power loss. It began to get worse and if you reved it up under or not under a load, it would begin to break up after 2500 RPM. The strange thing is that it doesn't set the "check engine" light. It did something like this once before but it was much worse but that time the check engine light would act like a strobe light going off and on. So I changed the computer and all was ok. That was about a year ago. I changed out the computer again this time but that didn't solve the problem. I thought the coil might be breaking down so I replaced it and changed the fuel filter but no fix. Talked with a buddy and he said that it acts like the fuel pump is pumping right pressure but not pumping enough volume. The car all but quit today, so I changed the fuel pump and no fix either. Any body got any ideas?

 

I'm not saying this is a fix, but you can test the Distributor by disabling ECM timing control and with a timing light watch the timing at a steady 2000rpm if the timing jumps around the distributor may be having problems.

 

Timing that jumps is usually a chewed up distributor gear.

 

Yes, usually, but in my case the hesitation and power loss was a worn dizzy and it's a easy test to perform. If it does jump around then he can pull the dizzy and check the gear. Still even this may not be the problem, just a suggestion.