Hi, I have a P0307 misfire code (misfire in cylinder # 7) on my 03 Ram pickup 5.9 gas, I replaced the Rotor, Cap, Wires & Plugs and a couple months later the Engine light comes back on and now I'm showing (P0307) code again. Any idea what could cause this. Thanks for any help. Glenn

 

What kind of plugs did you put in i have heard of people putting higher performance spark plugs in there vehicle and then it ends up running worse then just a cheap set of plugs couldn't tell you much more seeings how you changed the wires on them good luck in finding the problem though.

 

I don't know what plugs.... the Dealer did the work while still under Warranty and charged me $600, now 13000 miles later and (OUT OF WARRANTY) the same P0307 code is back and I think the problem was bigger than the quick fix they gave me (tune up)while still under Warranty.

 

I thought 2003 was the first year for the Hemi, and the ;ast year for the 5.9 was 2002? Maybe I'm mistaken. I would first check all the wire connections, and spark plug torque. I've seen so many problems that were just little fixes. Did you take out the spark plug? Check all the little stuff before you start thinking of anything serious.

 

The5.9 was an option on the early build 03's. The Hemi was added sometime around mid year 2003.
Dan

 

No I didn't.... I figured that the Dealer just put this stuff (Rotor, Cap,Wires, & Plugs)in just 13,000 miles ago it must be something else. If I take the plugs out and they're shot after only 13,000 miles wouldn't that mean I have a larger problem?

 

You never really know until you look. After working at a dealer, I've seen it all. I've seen caps that arched between 3 cylinders, electrical parts that were bad right out of the box, etc. Maybe the spark plug was not gapped correctly, or the electrode was a little crooked. I've seen thathappen afew times in the past. Or maybe you've been getting bad gas? You won't really know until you either check the connection at the plug and/or remove the plug.

 

Well I guess it's back to the Dealer so they can have their way with me (AGAIN)

 

You need to make sure the injector is working.It could also be bent or stuck valves. If you had a problem while under warranty, it could be covered as a pre-existing condition.

 

If one of those things were the problem (valves or injectors) would a Tune-up turn the "check engine" light off for a while?