Hello, I am new to these forums. I recently purchased a 2002 dodge dakota sport with the 4.7 v-8. It keeps coming up with a check engine light and the code is p 0301, which is a cylinder 1 missfire. After having it hooked up to a missfire machine it shows several cylinders are missfiring. I have changed the spark plugs, swapped coil packs, put new fuel injecter in cylinder 1, changed oil, and had the cylinders checked. While driving it has no misfires, after shifting from park into drive the misfires start popping up. Any one have any advice. I have been to 6 different places and no one can figure out the problem.

 

need to check for a vacuum leak .. Intake or a hose .. the truck could be getting to much air from the wrong source causing the engine to miss ..when hooked to a vac gauge it should be between 17-20 inch's of mercury .. Any fluctuation or a lower unstable reading will indicate problems ..

 

I already had the truck tested for vacuum leaks. sorry i forgot to add that. everything is checking out fine. Any other ideas? Also thank you for the input

 

Did you clear the code? Unplug the battery?

 

Yes i have reset the light several time.

 

What spark plugs are in the engine now?

How's the fuel pressure?

The cam/cranks sensors help set the ignition timing. I know you aren't showing a code for them but I'd check all the connections and even consider replacing them.

It could also be the PCM.

 

I have an 02 dodge dakota, put a pcm in it, now none of the lights work. headlites, taillites, door ding ,etc. Need help with this. Hoping its the ctm. Read here that I could unplug it along with taking the cables of battery and it would reset itself. think that will work?

 

Are the misfires happening on the same side of the engine?

IE: 1,3,5,7?

Could be your O2 sensors. Mine was backfiring too and I made a video (search the forums for "Backfire From Hell").

I bought the truck knowing it had this problem and it had been to the dealership 3 times and they couldn't tell it was a bad O2 sensor.

Brought it in to my mechanic and he had it solved within a few hours - was an upstream O2 sensor.