Originally Posted by Big Evil
Sounds like the Torque Converter Lock up (TCC) engaging and disengaging. That can be caused by a bad/intermittant read from the TPS or a faulty solenoid in the tranny. Throttle position sensor would be where I'd start looking first, I've seen tranny replacements done 3-4 times on the same car and it didn't fix that, but replacing a single sensor not even in the tranny did. Maybe this helps.
Thanks, I am assuming that replacing a sensor would be cheaper than the Transmission. If so then this sounds great, I'll try to start with the Throttle Position Sensor then.