R53 goes in to limp home mode (GOT towed to the shop)

So first this car thows up codes that had to do with pedel position and throttle body and cam positioning sensor.

cleared codes and the car was driving normal test drove for 2 hours and was driving normal.

drove fine for a week

limp home mode strikes again. (turned the car off and turned it back on and the check engine light was still on but.. driving normal)

trouble code was cam positioning sensor

The mechanic noticed a coil that had corrosion on it.. said this may set off the limp home mode due to the Y firing of the coils or somthing like that. Or may be the ecu but it was running fine again "lets see how this does" cleaned it and did a full tune up. plugs, wires, air filter and oil change, just for piece of mind since it we bought a used car.

cleared the code.

week later

Limp home mode strikes again. twice in 6th gear and once at a light..
Turned it off and turned it back on.. check engine light was still on but driving normal.
Same code about the cam positioning sensor..

-CPS was replaced "hope this does it.. the ECU is doing what it is supposed to be doing when something like that fails...



!!!!!!! LIMP HOME MODE STRIKES AGAIN on the freeway check engine light is on... Turn the car off and turned it back on driving fine.. Happends a second time same thing turn the car off turned it back on driving fine... At a light the car with in to limp home mode as i go to take off... TURNED THE CAR OFF AND TURNED IT BACK ON IT WAS DRIVING FINE. thankfully we were right by the house..

WTF???

has anyone had an issue like this... could it be the ECU...