Well, after adding my CAI, muffler and replacing my O2 sensor, I have noticed an odd problem. After shutting the truck off, and it dosent matter if it is for 2 seconds or 2 hours, you start it back up, put it in gear and try to take off and the truck try's falling on its face, rpm's drop, and it will lope/shudder for no reason. You let off the gas, and get back into it and the problems go away and all is fine. No codes are coming up, so what could my problem be?! I have replaced the IAC, TPS, the pre cat O2 sensor, cleaned the throttle body. My first thought was maybe the crankshaft position sensor, but I would be getting a code, then I thought maybe my cat is clogging up, so I will be replacing that with a piece of pipe to see if the problem keeps up. If that dosent help then I will take it to the shop I guess.