I have a 2006 Chrysler T&C 3.8L 140k have changed coil pack(3times), plugs, wires, injectors, valley & plenum gaskets and engine oil. Even tried swapping positions of injectors, plugs & wires. I have visually inspected fuel rail harness but still P0303 keeps reappearing. I bought this vehicle 10,000 miles ago, runs great and miss is only felt at idle.
Could it be a vaccine leak near cylinder 3? Just curious to see if that has been smoked out yet, also cam/crank sensors after? Don't know too much about Chryslers.
@bruceree
maybe that cylinder has COVID 😆
@bruceree
I did the smoke test, it passed but changed the gaskets anyways
@g-t
I did a compression test, it was normal.
Is it possible to swap sensors? Perhaps there is a problem.
@g-t
What sensor? Where is it located? My next move is to replace the ECM as a last resort.
Crankshaft position sensors
Check the fuel pressure.
@mountainmanjoe
that I haven't done but why would only one cylinder be affected?