[MMGT1]

Mike... timing requirements bud. I bet with the heads done we need to bump your timing a couple of degrees going from P/N to D. Your idle should be 775 no matter what position your in, and with ac on or off you should still be 775. Your saying your dropping to 400-500 and then working back up to 775 right? That is where your stall saver kicks in and adds timing to prevent the stall, then the IAC is catching up getting you back to 775. Like I said, pretty sure a little bump in timing for the transition will fix it