1989 Chevy Corsica Engine fades intermittantly on long jour

Need some info to help you.
Check engine light come on?
Have you had it checked for trouble codes?
When it fades is it like it runs out of gas a slows down to a stop?
Let me know

Thanks for replying:

It doesn't act as if it has run out of gas, it just, smoothly, gets gradually slower and eventually rolls to a stop. The engine is usually still running but the power has completely gone. If I increase the gas pedal it stops completely. So, what happens is, after about 50 miles or so, just as I am about to overtake a slower vehicle, the power starts to fade. If I put my foot down further on the gas the quicker it fades. The curious thing is that if I leave it for about 10 minutes, she starts up and sometimes goes on for about another 10 - 15 miles and, sometimes, the problem goes away for a while. Then, just when I start getting confidence in the car again, she acts up.
Look forward to your further comments, Thanks JP

Need to know chcek engine light on?
Trouble codes go to Auto Zone they can code it then ket me know the codes.

Will do, thank you, speak later, regards, JP