Hello I been struggling with my durango with p0172 I replace many parts, I replaced cylinder head due the p0300 I had on right side due to camshaft/ Rocker arms fail, I done cam relearn after replacing them now I have p0172. I replaced oxygen sensor, I smoke evap and did vacuum test still same I done all coils packs, fuel injectors and spark plugs, I still can't figure it out. Any ideas