Im new at this, but when i changed over to the 2002os the engine run fine, but my IFR was way off for the COS5 autoVE,so i had to recalibrate it and now the IFR is right, but way lean, so i had to raise the VE table to compensate for it, Could the COS5 have any thing to do with this. what should should i set the parameters:A0007, A0009, A0010, A0015, A0016,To keep them neutral. or cause no interference. In my 2000 tune , i used the IFR to add fuel to my car. I know this was not right but i didnt know any outher way of doing it at the time ,But A.J. (whytryz06) has been helping me learn the right way to tune over the phone. The engine is running and been doing autoVE logs. The bucking has stopped sense I raise the B4205 to 284F. Thanks joecar.