Hi scotty, I need your help please on a 1992 Chevrolet c2500 5.7 350 v8. One issue I have is that the truck high idles when I start it and when I put it in either drive or reverse the rpm drops and the engine wants to shut off and I have to press on the throttle as soon as I put it in gear or else the truck will shut off and it takes a few tries to start it back up. I also noticed that the truck has lost power because I used to burn tire on that truck and now it doesn't. Another issue I have is that too much smoke comes out of the exhaust and I noticed that I have poor fuel mileage because the gasoline drains fast. I think it could be the MAP sensor that is causing the first issue and the oxygen sensor that is causing the other issue but I am not sure.