[89IROC&RS]

actually then i would say its an intermittant short to ground on the TCC circut, a wire rubthogh somewhere that is grounding the circut and causing the converter to lock and unlock. probly somewhere on the engine, as you brake the engine moves, in the same way everytime, or let off the throttle it moves the same way. so find the TCC sensor, and chase that harnes till you find a rub through, and fix it. no more surge.