98 contour transmission problem

I have a 1998 ford contour with the 2.0L and automatic transmission. It has 171,000 miles. Here recently it has been acting funny. When i am driving along sometimes, it seems like it downshifts and the motor revs up. But it doesn't really downshift. In the past when i would be driving(in 4th gear) and would let off the gas and then press the gas again it would start with the motor revd a little higher then go back to normal. Not really shifting though. Another symptom is that when I drive at 55mph it seems to be reving higher than it use too. Does anyone have any ideas??? Thanks alot, Jarod

Welcome to AF. The lock up on the torque converter isn't working. It could be a solenoid. Check all the elctrical connections you can find down around the transmission. Unplug them, clean with some alcohol and then plug them back up. I know you have done this, but I have to ask. Did you check the transmission fluid level?

Yes, and it was just above the full mark and was a little dirty. I also added Slick50 additive about a month ago to see if that would help. I'll look for electrical issues. Thanks

I tried checking all the electrical connections. Cleaned the dirty ones and unplugged and plugged in several times. Have drove it the last couple of days and still have the problem. Filled up for gass and a few miles down the road the motor increased RPMs like it down shifted half a gear. It stayed that way for 40 more miles of driving. Could old fluid cause this kind of problems? Thanks again, Jarod