First post. I am hoping some can can help - thanks in advacne
2000 GTP Coupe- took car into dealer for valve cover recall. also had dealer replace, plugs, wires, two coils. car came back idling and running faster than it did previously at all speeds according to tach. it is not shifting correctly either. took it back to dealer twice to fix the issue. had a complete diagnostic run on it and everything is according to specs. gas mileage has dropped 6 mpg and it apears to be running rich. replaced maf, cooling, idle air sensors, air filter. also put all the original wires, coils, plugs back into vehicle. car has been tuned with cai, sc pulley, vers 1 performance pcm, flo thru mufflers, ubend removed, purchase new vers 1 pcm and tried that. no change. put original pcm and tired that, no change. the mechanic who worked on vehicle had it out of garage for several hours. something was done to engine or trans accidentally or intentionally. I just want my car back to how I had it performing. highway mileage was 30 to 32 mpg and city 26 mpg. now, highwsay mileage is 24.9 tops and city 19. what can I do before I commit hari kari? ...neverenuf
Originally Posted by W-Body Store
