ballajb

I have a 5.0 H.O. motor from a 1991 mustang. F303 cam, aluminum heads, 1.7 rockers, typhoon upper and lower intake and 5speed. For some reason my rpms do not go past 3500 while driving. what could be the cause of this?

AdderMk2

bad maf, clogged cats, incompetent builder, really bad valve springs, fuel delivery problems.

could be MANY things

uedlose

does it miss when this happens more INFO

BlackMage

i was having the same problem and my pick-up coil in the dizzy was bad....

mstangblue123

when my transmission was rebuilt mine would not go past 4k-4,200 and before the rebuild it would shift higher..... might be a tranny problem