No acceleration above 40 mp on 1991 Pontiac Trans Sport

My vehicle doesn't accelerate when the vehicle reaches speeds of 40 mp to 55 mp. Tachometer indicates increase in rpm, but the vehicle doesn't increase in speed.

Asked by for the 1991 Pontiac Trans Sport
This could be a transmission, plugged exhaust or an issue with the fuel/ignition system. Better get it looked at for a diagnosis, here are some shops in your area: