I had a PI 3000 Stall put in a couple months ago. When I had it put in, the shop that installed it said they had to sand a little bit of material off the transmission shaft so the converter would go on fully. Well it worked wonders knocking .35-.4 off my 1/4 et. However I would notice sometimes cruising at say 30-40 mph anything more than 1/2 throttle would cause the car to rev up all the way to redline before the converter would lock up and cause the transmission to shift. Lately itd been getting a lot worse. Now from a stop the car takes forever for it to start going, I mean itll rev at like 3k for like 4 or 5 seconds before it catches and starts to roll forward. Once it gets going, it drives just fine. Its just from a stop. What could it be? Ive checked the fluid and its fine. Someone please help.