1987 Suburban

Help I have a 1987 suburban. While idling it sounds like it is going to shut off. It makes a puff sound from the exhaust pipe w/ light white smoke puffs. It seems to hestiate when going down the road. I had the plugs, wires, MAP sensor, O2 sensor, Coolant sensor circuit and distributer cap all replaced, it still runs the same. What could I be missing? Please help. Woman in distress......

If you haven't had it done, you should get the timing checked and if its a TBI the throttle body unit itself can get clogged up and can use a good cleaning or rebuild. Also, check the "Chevrolet Suburban" forums, there seems to be alot more posts over there....