22re engine shuts off after running 30 min

[david77]

I need help with my 22re engine in my 85 gts convertible. engine shuts off after running for 30 minutes or so. i have changed the following, igniter, computer, dist. all plugs and wires, fuel pump, injectors, alternator, relay on pass. shock tower and battery, etc. The engine loses power after running and starts to shut off. It seems to be worse when I turn the lights on, so I am thinking now that it is an electrical problem. Also car has 57,000 original wiles on it. was stored at a beach house. have rebuilt engine, but did not change any of the original wiring harness.

could the problem be in the electricla wiring harness?

any help would be greatly appreciated!

[Dave88GTS]

Possibly alternator is going bad, car may be runing on battery till it dies.