I have a 2001 Ram 1500 with a 5.9, it wis getting a misfire cyl 1, misfire cyl 3 and multiple cyl misfire code. The only time you use to be able top notice a mild misss was at idle, now it has worsened and misses terribly wqhile driving. The cap plugs rotor wires and o2 sensors have been changed.

 

If you already looked at plugs, and coils, try doing the cylinder leak down test and a compression test on every cylinder.
or
take the valve covers off, look close to see if any rockers come off, Ive seen it happen on the 8 cyl.

 

Compression test would be good. Also check out your crank position sensor. It acts as the pick-up plate on the Magnum motors.

 

how is your cat? has it been replaced? does the motor dog down when you get on it or does the exhaust sound any different?.

also make sure your plug wires are routed correctly acording to the TSB found at dodgeram.org

i would defantly start with a leak down test .. results should point you in the right direction

 

Could be some crazy clogged injecters too. Do a Comp. test first cause its easy [:'(] Off the top of my head suppose to be 115-120 psi?

 

Almost identical to how my problems started... ended up being a blown head gasket. Truck been overheating at all? Is your coolant full and/or is there oil in it? I finally figured it out by watching the coolant pour out of the overflow while the truck was running. The pressure from the cylinders was over-pressurising the cooling system. Good luck!

 

Check your injectors. I had 2 misfires as well, did the cat (it needed it) wires, rotor, cap, plugs, and it ended up being clogged injectors. I still have a few old ones that i kept becuase they werent clogged and i changed all 8 of them. There from a 99 1500 with a 360. I know they were a big expensive and ya can probably use these, I would just suggest changing the rubber o rings on them before putting them in. If ya need any though, let me know. My email is JBKucera@warwick.net. Good luck man