I need your guys' help, I am ready to drive this thing off a cliff! When I accelerate it stumbles, but when I start to let off the throttle it picks back up. I have checked the timing and its alright, just decided to replace the cat after 198,000, no difference, and the code scanner says theres nothing wrong. Any one have any input on where to go besides the cliff? I am leaning twords a timing advance problem but don't know where to look with the TBI/computer system.