Started few weeks ago car went into limp mode. Stopped car and restarted it, all fine. Yesterday car went into limp mode and missing at idle with check engine light on, seems to drive fine once moving. It's a little harder to start bit more cranking than usual but starts np. Idles between 750-800 but rough. Codes I got are po300/po301/po302/po303/po304. I reset the codes and car is running fine now?? Any opinions as to what my problem or problems might be?? Any and all help welcome. Car is an 02 A4 1.8t.