2004 5.7 hemi with high mileage. Starts with no problem, but has rough idle which smooths out at higher rpm. No odd noise from engine. Pulled plugs and they are black & wet. Exhaust is white when accelerated & smells of fuel.
No loss of coolant, No loss of oil. No codes.

Now - clogged cats? Valve issue? O2 sensors? What else????

 

Getting any codes?

 

Clue #1 - wet spark plugs - spark plugs should not be wet. This indicates that fuel is not being ignited.
Clue #2 - fuel smell in exhaust - This is also a sign that fuel is not being burned properly
Clue #3 - high mileage - Could point to a burned out ignition coil

Possible Causes:
1. First thing I would do is replace the spark plugs. Make sure they are properly gapped.
2. Second thing would be replace the ignition coils. Could be bad with really high mileage
3. Third, anything more serious than this would need a diagnosis by a technician.

Good luck. Let us know what you figure out.

 

Replaced all spark plugs. Replacing all wires.

 

Replaced wires yesterday & still have a rough idle. Maybe it's me but gas smell has lessened when running at idle. Next item - replace all the coils.

 

I realize there are no codes but I would be considering a compression test before throwing more money at it.