Could this be a malfunctioning TCC Solenoid? The symptoms are....cruising at highway speeds the engine will rev up 500 rpm'* and then go back to normal. Sometimes the engine light will flicker and I will hear a "ding ding" the interior chime will go off when this is happening. Also occassionally at a stoplight the car will just stall, kinda like there is a load being applied. Then the car starts right up. I've had the computer read and its blowing po131 so I changed the O2 sensor, reset the computer and it still does the same thing. Also forgot to mention that I lost Overdrive a few weaks before this started to happen. Doesnt the lock up solenoid need to work for overdrive to work. Someone please point me in the right direction. THANKS in advance.

I had a 98 grand prix that did that. Changed the TCC solonoid and it was still there. The tranny shop said it may be a worn input shaft and that the trans basicly needed to be rebuilt