2001 A4 2.8 v6 30v

the misfire happens when the car reaches the 3,7000-4,000RPM and its always the first 3 cylinders. I was using AllData from a mechanic i know and we checked everything. We started with the fuel filter (which hadn't been changed since the car was bought.) replaced that. next we checked the spark plugs, then wires, then coil pack, and everything was to specs of alldata. my mechanic said he thinks its the engine speed sensor since it only misfires in the first 3 cylinders (we changed the wires so that cyl 1,2,3 were plugged in to the coil 4,5,6 but still the first 3 were giving the misfire)

he checked the fuel pressure and said that was fine and the car was not misfiring when idling. only when it got to the higher RPMs. I have been driving it around and when it would misfire i would not feel loss of power like what cars do when they do misfire(shaking, shuddering...)


What do you guys think?
any other info that you guys might want just let me know.

Thanks