Need Help Please! 98 Mercury Tracer

[Heather77]

I need some help trying to figure out what is wrong with my 1998 Tracer. Here is what is going on:

My car slips only between 40-55 mph and only between 1500-2500 rpm.
It does this only when it up-shifts. It starts acting up after a few minutes of driving. Some power loss and gas mileage has gone down.

The transmission fluid level is fine and fluid is good. I recently had my timing belt changed, antifreeze changed, new water pump, new fan belt, brakes and rotars, and an oil change.

I know that I have an exhaust leak that I need to have fixed. I would greatly appreciate any advice. Thanks!

Heather

**I should also add that this is an automatic transmission, 2.0L, 139,200 miles, 4 door**