I have a 2002 Ram1500SLT with the 4.7 motor. It has 150k+ miles on it and have had no mechanical problems before. The only aftermarket part installed is a Volant air intake that has been installed several years back.

Started running poorly so I installed new spark plugs. Still ran rough. Hooked it to a computer and came up with code P0308. Was told this code was a misfire in cylinger #8. Was told it was either the coil or injector. I installed a brand new coil in #8 and still has the misfire. I then installed a brand new injector in #8 cyl and still have the misfire.Both parts were replaced with OEM Mopar parts.

I'm stumped and my next step is take it to the dealer. Is there something else I should look for before I run it down there. Obviously I want to save money but if I have to I'll have to take it to the pro's.

Thanks in advance for any/all advice.

 

Plug wire? You're way past due for those. BTW, don't necessarily expect "pros" at the dealer.

 

Possible causes in the factory service manual are:

(K342) ASD CONTROL OUTPUT CIRCUIT

(K28) INJECTOR CONTROL NO.8 CIRCUIT

(K98) COIL CONTROL NO.8 CIRCUIT

IGNITION WIRE

SPARK PLUG

IGNITION COIL

FUEL PUMP INLET STRAINER PLUGGED

RESTRICTED FUEL SUPPLY LINE

FUEL PUMP MODULE

FUEL PRESSURE LEAK DOWN

FUEL INJECTOR

ENGINE MECHANICAL

PCM

Troubleshooting procedure is extensive (8 pages) and requires special tools. A friend of mine had the same issue recently. He spent a bunch of money replacing parts before going to the dealer so I think it is worth taking it in. Good Luck!

 

Truck doesn't have plug wires. Each spark plug cap has its own ignition coil which clips into the the wire harness which eliminates the need spark plug wires. BTW, I would rather send it to a "PRO" who works on these day in and day , who has experience with my particular truck and may have a least experienced this type of problem before versus a shop that will work on anything that comes their way.

 

Thanks Gunnar, that's what I was looking for!

I'll probably end up taking it in this weekend, thanks for the input.