Im trying to get mustang that i have for sale running as smoothley as possible before i sell it and im having a bit of trouble with the acceleration. It has the normal low end acceleration fine but once i hit 4000rpm it begins to flatten out. It was never like this before, first i assumed it was carberator problems and began taking a closer look and all of the flaps are opening good (4 barrel carb.) So i thought it would be the spark plugs, i changed all my spark plugs today and retimed them. Nothing...
I dont know if anyone on this site can help me out with advice on an older domestic car but any suggestions would be appreciated.. i try to keep that car as mint as possible so this is really bugging me.
Thx.