First, sorry if there is any wrong spelling or grammar. I have been using a PPE xcelerator and love it. 2003 lb7, I changed the tune the way I always have over the last year with this programmer and now my truck will not start or crank over. I replaced the batteries, checked all fuses/relays hood and cab. and the starter is good. I have power to everything in the truck and there is no seen wearing of the wires from the fuse box from fender rub. When I hook up the monitor it will not let me return to stock and it reads, reading the stock vin against the programmer vin. And will never go away. When I try to change the tune it will pull up an error screen showing key error 762f and speed error 0000. When I called PPE I was told that means nothing to him. If anyone has any advice that would be great. I ordered a new ECU but not sure if that will fix the problem. I have thought about the neutral selector switch as well, that will be after the ecu if no fix.