My kids car is a 99 sunfire with 150k has the 2.2 the trans is not overdrive i think. Anyways when you go down the highway at about 70 to 75 it is running 3500 rpms and sounds like it is about topped out. I'm taking it in to get the trans flushed and hope that helps. I had to replace motor mounts because they went bad. Is that normal rpms for that car or is there something holding it back?