My NA had a mechanical speedo and the turbo is a rev 2 so electronic. While I am waiting for my mech speedo drive, I get the check engine light occasionaly and it is error 42 IE speed sensor error. Does this have to do with the electronic speedometer? Does this error effect the engine in any way? I also seem to be getting an erratic fuel cut when reving over 5k and on load.
But my guess is an incorrect fitted walbro pump or the tank not venting properly.