Ok here is my story... About one month ago I was having problems with the MAF signal. My car was hesitating and hitching when I was crusing on the highway. This problem went from happening once every ten min at 1st to later it was impossiable to drive the car. I ordered a new MAF that was bigger and Calibrated to match my injector size, I entered the meters Flow specs into the TwEECer and made a 30 point MAF Transfer, I played with the MAF signal and got the car running great. The car worked fine and ran great on the highway and in town. Until the other day I started to get this same hitch and hesitation on the highway again and the car became impossiable to drive. I did not change anything with the tune. In order to get my car home I unpluged the MAF and ran it without the MAF, I was able to get my car home this way as long as I kept the RPM up. When this hitch/hesitation happens I do not have any drop in fuel pressure. But my A/F gauge seems to drop off Lean then come back to normal. I have changed the fuel pump relay also. I unhooked the computer and the MAF meter and cleaned all connections. My car was Speed Density orignaly I went out and bought a Mass Air conversion kit from Ford. Which has worked fine up until this year. My computer is a A9S... I have been using the A9L.bin file for the stock/base tune. Would my files on the TwEECer be getting corrputed some how? What might be giving me the problem.. do u think that the Mass Air conversion is starting to give me problems? Any help would be great.. sorry so long.