My 1996 automatic Dodge Neon with 51K has two problems. The first is when I turn on the heat in the car, the car seems to "idle and rev" loudly. Second, just last week I noticed that the automatic shifting from about 30-35 mph seems to hesitate and it feels like it is hard for the car to automatically get into the next gear. I checked the ATF and I need to add more, but will this solve the problem? I seem to be getting poor gas mileage although I just had a tune up. Thank you from a concerned female.