My safari minivan runs rough cold. it runs better after warming up. I have replaced faulty Bosch 02 sensors twice. Still has a PO300, and now it has a PO175 code.

What is your question?

What could be wrong with my 2000 GMC Safari Minivan,2 WD? It has a PO175 code and a PO300 code from time to time. I have replaced a lot of things, but it still runs poor cold, better warmed up. Will drive down the road 80mph + but sputters, spits and bucks like a wild mule from 0-40 mph.