1997 Subaru Outback Oil in my air filter

Just did a head gasket job, replaced the timing belt, ac and alt. Belts, the water pump, PCV valve, all the gaskets, plugs and flushed the system. When we try to start it, it runs TERRIBLY, choppy, wont stay running, then idles REALLY high, backfires and dies. We have redone the timing belt 3 times, counted the teeth and put it all back together just to have these same problems. I keep getting Hot (smokes) oil in my air filter and the same 3 codes, MAP sensor, Cam. Pos. Sensor and Crank. Pos. Sensor. We are stumped. Please help us save our subaru (2nd head gasket job in 5 years) I understand the donation part, but I need help first.