Check engine light goes on anf off on 1991 Chevrolet 3500 Pickup

After driving for 15/20 miles the C.E.L comes on, if I stop, turn the engine OFF and then restart it, the C.E.L stays OFF for another 20/25 miles, then comes ON again...and I think I smell a "burnt" odor.
It is a Chevy 454 (on a Pinncle MH)
Thanks a bunch

Asked by for the 1991 Chevrolet 3500 Pickup
2 answers
Have it scanned for codes. Then will be able to tell you more.
scan codes and post so we can adv