1990 LX motor kills
 

After it runs for a time my motor idles down and stops. It runs for varying lengths of time, sometimes an hour, sometimes a few minutes. I have replaced a lot of parts: distributor, igniter, fuel pump, fuel filter, fuel pressure regulator, fuel pump relay, sparks, wires... still no luck.

Can it be the exhaust manifold? or what?

I have the same problem i am at the point now where i think its the Ignition Control Unit Module but i still dont know. I have changed the fuel filter,fuel pump,plugs, wires,took the gas tank off and cleaned it out put good gas in it. I will crank and run very poorly untill it hits about 4000 RPM,s and then its like all the cylinders are running then. i dont know whats up with it any help i would appreciate it!