I had a custom tune done to my truck while out of town. Now the computer of the truck is locked, its running lean 15.4:1 and some sometimes 17:1. there is a dead spots a 5000rmp and misses a bit till 5400rpm then it wakes up and sets you back in the seat. run slightly rough at idle (950rpm). Its a gmc yukon Denali with a 6.2l vvt comp cam, biggest they make. Ported heads and kooks headers. Comp cams valves springs and lifters and push rods. Any one have any ideas or do i need to get another computer. P.S. when accellerating heavily its is at 12.8:1