After getting the pulley/tune/tcu treatment a month ago I was experiencing lurching on takeoff and wondered what was wrong thinking that perhaps the ecu/tcu was interacting with the wheel spin limiter in a positive feedback loop.
Here's what it turned out to be. The car now has so much torque and the ecu tune has made the throttle so snappy that the g-force on takeoff was pushing me back in the seat and slightly pulling my foot off the gas pedal without my realizing it. Then I would instinctively give it gas because the car had slowed suddenly (of course!) and it would all happen again. So, my car is suffering from newtonian porpoising :-)
The fix was to move the seat down to get my knees lower and below the knee bolster on the bottom of the dash and to brace my body with my left foot before pushing the fungo. Now, we're having FUN!
Has this happened to others out there?