My 86 DeVille runs perfectly, for about 10 miles, then just quits and won`t restart for about an hour. Seems like no fuel. I have replaced the fuel pump, fuel filter, ecm, ISC, Temp control sensor, and am at a loss. The only codes that come up are related to my air conditioner, which is non functional. However, my service engine soon light is always on, and has been since I bought the car.

Welcome to AF. What is the code number one, 2, do you have injector pulse, does fuel spray from the injectors in the TB, do you have spark, all basic diagnostics.

Try a new ignition coil.
The coil works ok when cold, but develops too much internal resistance when hot, leading to a weak spark.

The symptoms mimic fuel system issues.

Also consider the possibility of a failing ignition module.

Thanks for the replies.. I believe its a fuel problem, When it quits, I can put fuel into the throttle body and it will start, but just burn off that fuel.Its almost like it is getting a signal to shut off the fuel pump.

Check the fuses of course and the wiring at /around the oil filter, they can get shorted or pinched in that area.