i have a 1991 5.0 auto. about a month after getting the car i started to have a problem with it. it feels like the car has no power. once the car hits 2k-2.5k rpms the y drop down to about 1k and after that even with the gas all the way down the rpms increase very slowly.someone told me it was because my converters were clogged so i installed an h-pipe but im still having the problem. the car also has a rough idle at times. anyone have any ideas? thanks