i asked this question in the 3rd gen forum but not to many have the 5.9 so here it is again maybe im asking the right people now, i have a 03 ram qc with the 5.9 gas, my engine light was blinking in the morning on the highway a couple of weeks ago so i went on here and was told might be the o2 sensor or wires, so i did wires, cap, rotor on my truck. all was fine , now this morning the light stayed on and showed code p0300 so i went to autozone where they read the code and said clyinder 2 and 8 misfired , so what can i do to fix this or dod i need to go to the dealer to get a nice big bill to fix my check engine light? also when i did the wires and cap, etc i didnt put plugs in i dont know if now it can be the plugs. thanks for the help!

 

Misfire code is what it is for sure. Make sure the wiresare seperated properly n not touching eachother or the intake manifold or exhuast manifolds or basically anything that can ground a wire. That misfire codeis for ALL makes on OBD2 systems it doesnt matter what you have Chevy, Dodge, Ford, Mercedesor whatever it will say P0300 if theres a misfire on more than one cylinder.

 

Yeah, the PO300 is a generic misfire code. Maybe the Autozone folks have a more comprehensive code reader to give the exact locations. At any rate, what hellacios said; check the plug wire routing very carfully. Since 2 & 8 are in the same bank, its very possible the wires are running too close together between 8 and the dist. cap. Did you use the separators to clip the wires in place?
The FLASHING MIL would concern me though. Generally speaking if that lamp is flashing, pull over NOW and see what the problem is. But if driveable still, (and not having a code reader) have the code checked 1st. Then check here.
WC

 

Hey Python, got an update on this. My 5.2L is doing the same thing. I changed out the cap, rotor, wires, and plugs. Used a plug tester to make sure I got good spark (I do) Still not running right and throwing codes. P0300,P0301,P0305, P0304. All of them misfire codes. Checked engine vacuum for a vacuum leak and cant find anything wrong there. I changed the belly pan gasket on the intake manifold a while back, but vacuum check would have shown if I had a leak. Checked cylinder compression and that is good too. Checked fuel pressure and it is a little high 45 psi w/ engine running. 35 psi w/ engine off, key on. Checked the Camshaft PS, Crankshaft PS, ASD and Fuel pump relay, fuel injectors, and the ignition coil. Everything came up fine. Darn near ready to pay a shop to find and fix!!!! Any help would be appreciated.

 

Get a pressure check on your exhaust system. A clogged cat will cause a misfire code.

 

Replace the cylinder heads. This a common problem with all dodge trucks with 60k miles or higher. reman heads are avilable thru the dealer and they come with valves.