Chevrolet Repair: Re: 1002 chevy pickup problem, pvc valve, vacuum line

Question
Hi Mark how are you today. ?? I have a 1992 chevy pickup V6 motor automatic transmission. it has 365,000 miles on it and has been running great till now. my problem is it is losing power  on the Hwy. it will only go about 50 miles an hour. it ideals smooth and transmission kicks in the gears, but loses power, i have done the following, changed Cadillac convertor out, ran compression check it shows 100-120 on 5 cylinders and 80-90 on one cylinder. i cleaned out vacuum line going to PVC valve it was clogged up some, PVC still vibrates ok. exchanged the oil 2 days ago. i put on new distributor and rotor yesterday. I put on new fill filter yesterday. new air breather yesterday, but its still losing power, I'm so confused now what it is, can you help me out Mark?  ASAP I'm going deer hunting Friday night I'm leaving.                    James

Answer
Hi James, Deer hunting is coming soon here for shot gun, as I sit here with a broken leg from riding my dirt bike. I hope to get out and just sit somewhere. Good Luck to ya!!

  OK, you have cleaned out the pcv line and port on the TBI unit, now lets make sure that the vacuum line going to the MAP sensor is also very clean. I would remove the TBI unit from the engine and pick,scrape and dig out the carbon build up. Make sure it is clean and all ports and flowing.

   If this doesn't fix it, the next thing to do is check the fuel pressure. Should have 10 to 13 psi, if not pinch off the fuel return line to see if the pressure goes up. If it does the fuel regulator is bad, if it doesn't..the fuel pump is bad.

   I'm thinking the tbi cleaning will repair this one!!

Have a Great Day      Mark