I bought a 260Z that had a early 280ZX Turbo engine put in it. The car will starts and runs fine while it is cool out. Once it has had time to warm up it begins to have a miss a small miss..It now has started to stall for no reason. I let it sit and it will start fine. I have started with the basics Fuel filter, pressure regulator, coil, plugs, water temp sensor and checked and cleaned the connections at the ECU. At this point I have to believe that it is electrical that only happens once it has warmed up. Any suggestions would be greatly appreciate..

 How long does it have to sit and cool down? before it will start again?

It will start in just a few minutes but misfires real bad. Once it under any load it does the same thing. Once it cools all the way it will run fine foe a while. 

 

 The fact that it doesn't run well when it's cold or under a load could indicate a lean mixture. Might be a good idea to install a temporary fuel pressure gauge so you can cross that off your list of gremlins. When it's idling and missing, have you been able to isolate the problem to any one cylinder? How do the plugs look?

I think you miss understood me. Everything is good when it is cool. When it is hot and it is restarted after stalling it miss fires real bad and that is when it stalls under any load.

Sounds like the ignitor (transistor) on the coil is going bad I thought that was a symptom of a bad ignitor when it would get hot. Google bad 280zx turbo ignitor symptoms. 

Also check for corrosion on the round 4 way plug to the distributor.

When it won't start see if it is getting spark or not.

Edited March 19, 20178 yr by JSM