He'* got the magnavox.
Does it backfire on the intake? And like make the airbox shake and make a loud pop? Mine did that all the time, then it went away, and it did it all up till I changed my ICM + coilpack. If your'* is backfiring out of the exhaust, it may be a different problem, but the ignition system is a likely problem. A tune up may be in order. A new set of plugs and wires.. or if you want to be cheap, make sure your wires aren't touching at all.. if they are, make sure you separate them.
'89 SSE - GX3 -190k, 155k on body - Back for another ride.