I have a 1996 Chevy Cavalier 2.4L Auto Transmission, and at constant speeds on the interstate the RPMs while running at a constant speed will jump from 2500 to 3500 RPM. Speed doesn't jump, just the RPM. Any idea's?

When I let off the gas, and let it coast, I don't get this problem, and I don't seem to have any problem when it idles either (smooth idle, no stalling)

Does the RPM jump like it's downshifting or like the transmission is slipping? Check the transmission fluid level and condition. It should be red, with very little (if any) brown color to it, and should not smell burnt at all. If it's brownish or smells burnt, have it flushed. Don't just drain the pan and refill it.

Does the RPM jump like it's downshifting or like the transmission is slipping? Check the transmission fluid level and condition. It should be red, with very little (if any) brown color to it, and should not smell burnt at all. If it's brownish or smells burnt, have it flushed. Don't just drain the pan and refill it.

It sounds and acts more like its downshifting than slipping.