The radiator cracked and I blew the original 1991 305 engine with throttle body injection. The only replacement I could find was a 1989 305 with tuned port injection. To save the wiring harness and PCM, I exchanged the intake manifolds. The TPI engine runs fine with the TBI manifold and PCM until the PCM takes over after warmup, then it barely runs at all. What can I do?

 

Sounds to me like once your oxygen sensor takes over is when your engine starts to die, I wonder if the tbi sensor reads differently from the Tpi, let me know what you find out

 

is the exhaust system currently connected?

 

That's probably when things started to go wrong. After charging $500, the first mechanic I took it to was unable to figure it out. The second guy spent another $500 of mine and told me twice he fixed it, but he hadn't. He agreed to keep trying for nothing and finally got it to work. He claims the PCM ran the spark advance to the limit and was still unable to set the timing correctly. He "cheated" by setting the distributor outside the spec and that did the trick. As long as I have your attention, maybe you can answer another question. The car starts fine when it is cold. After driving far enough to get the engine warm and I try to restart the engine, the starter is unable to crank it although it seems to be trying really hard. If I keep trying, sometimes it will crank as if nothing is wrong, but most times, I have to wait an hour or so. Then it cranks like it was new new. Any ideas?