Hey guys. 2010 t&c with a 4.0. 66,000 miles on it. Recently i got a p0300 code in the van so went on a search. Reading the LTFT on my scan tool i realized it had a vacuum leak. Replaced upper intake gasket as it had flattened and was no longer sealing well. Light stayed off for a while (few weeks). Came back with a P0306. Saw spark plugs were worn (a bit early, huh?) and replaced all 6. P0300 came back and i then checked coils (at this point i know all the fastener sizes and torque specs lol) and all coils check out. Coils are fine (checked resistances). Upon checking them, i switched them all around randomly so i had no clue which went where but still, P0300 and P0306 come back. Realize some oil was in the #6 cylinders injector plug so i sprayed it out with MAF cleaner both plug and injector and dried with compressed air. Light stayed out for a few days and then came back on AGAIN. So now i've got P0300 and P0306 which come back consistently. In the beginning it was P0300, then fixed upper intake and came back P0306, then both keep coming back. My only other idea is to pull the fuel rail, replace seals and swap them around to see if the misfire follows an injector. Other than that, i'm at a loss. O2 sensors respond fine. No other vacuum leaks i can detect. Other than swapping injectors and doing a compression test, i'm out of ideas. Just chased this same P0300 code around on my grandfathers silverado and found out that two lifters collapsed and the camshaft went sour. Anyone have any idea what this could be on this minivan? Anything common? It's getting fuel. Obviously a P0300 has to be something common between all cylinders, but the P0306 is what's throwing me. Is it one cylinder causing the P0300 or what?

 

Sounds like a coil problem but you've changed them around. Next best thing would be injectors right enough or a wiring fault to them.