I have a 1994 mustang GT 5.0 manual trans. that will sputter when it hot or cold and when we press down on the gas fully then we receive minimal power(slow rise in rpms) until we get to approx. 2000 rpms in which we will not get any more power. However we can still gain speed or get power above if we are lightly touching the gas. The current gear is not the problem. We can be on a 15 degree grade uphill and still be slowing down(not very fast but still slowing down)with the gas at full throttle but with just a little bit of throttle, we will get better response. Basically, on level or uphill grade, with the throttle at full we have extremely little power/response. but with very minimal throttle we get more power/response. Our beliefs is that it is the calytic converter.

 

run a koer test for codes if none ..check fuel pressure..if adequate pressure and volume...loosen doen pipes up to simulate an exhaust leak and if the cats are plugged you'll get power back

 

I've got my money on the cats.... it happened to me