the rpm will move about 200 rpm back and forth only when you are at a steady speed, if you accelerate or let off the pedal it doesnt not do this.

wonder what is going on thanks for the input

 

Sounds like the torque converter (TC) is locking and unlocking. When it does this surging, try gently pressing on the brake while you still have a foot on the throttle. When the brake light switch is tripped, the TC should unlock. While you foot is on the brake, the ROM will stop surging if it is a TC lock up problem.

 

I would suspect the converter is unlocking then relocking.
If so, it is noise in the computer input signal. Clean battery posts, wrap rarger brown wire from alt. area to passenger battery with aluminum foil! Then add a noise filter to the computer input signal. you can get them on E-bay.

 

I had that issue and got a apps noise isolator and been fine since