Hey guys, this has nothing to do with mustangs, but since i no theres a a few mechanics in here........my mom has a 98 plymouth voyager and when i was on the highway today ( i drive it enough to know it) the rpms will not climb past 2750 even when i put the pedal to the floor. It seems like it doesn't downshift but then before this I remember when you accelerate, there was a whining sound from the back off the car. It will pick up speed but very slowly and it never has done this before. Transmission has about 60k on it. What do u guys think this could be? thanks. oh and off the highway theres not a problem. It starts to happen when u get at about 70mph or 60.