well i just got the truck back from the mechanics today and it is still running like junk. she is a 92 k1500 with the 5.7. i took it in because i couldn't work on it anymore due to shoulder surgery. they said it was just the vaccume line going into the map sensor and that solved the idling issue and stalling out. so on the way back she would backfire like none other wile accelerating I've had this problem before but i fixed it with the distributer cap and rotor and it has never been this bad. and it was smelling like oil so i got her home and oil was actually coming out of the dipstick and burning on the manifold. (they probably just didn't put the dipstick all the way back in). so here is what i have done to it so far since i got it. fuel filter, air filter, distributer cap and rotor, spark plugs, and finally the O2 sensor. any input would be much appreciated, i am completely stumped.