dewman455

I just put 04 mustang manual on the road with similar problem. It would run fine under light loads but would buck strong under load. I watched a scanner while my son drove. The fuel pressure would drop from 39 psi to 2 psi under load. Turned out that inside the gas tank was very rusty. The large flakes of rust and coating would load up on the pump screen and block flow.

azstang86

problem was solved after changing the spark plugs, wires, ignition, and replaced a new fuel filter.