Valve Float - High RPM breakup
Luckily, LS1 PCM's have a decent learning curve. It will try to correct as much as it knows how to. Long as you aren't beating the crap out of it, you can still take it to a tuner and it should be fine.
Strange Im having very similar issue only every once in blue moon under accell or downshift then quick accell and it just stops accelerating like it just stops running until I let off throttle normally happens when shifting and fast throttle engagement. My wideband dips to 10:1 under WOT the when issue occurs my AEM wideband just goes blank "--". I let off throttle and vehicle is back to normal. Also strange is it happens everytime when in neutral wont rev past 4500 but will rev past 4500 when in gear. Still trying to track it down wonder if you fixed your issue??
