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Dakota Misfire issues

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Howdy Gearheads:

3 Months ago my 2002 Dodge Dakota 3.9L v6 4x4 started having several misfire codes,
P0304, P030,3P0302, and maybe a few others. I figured it just needed a tune up so this is what I did.

(1st)
Ran fuel injection cleaner in the tank every other fill up
Replaced all plugs and wires
Replaced the ignition coil
Replaced the distributor assembly
(that cleared all the codes except the P0304 and the truck ran a lot better, but still sputtered when started cold and lagged in reverse)

(2nd)
Took everything apart down the the fuel rail and cleaned every injector and replaced #4 cylinder fuel injector. I am getting spark and fuel to that cylinder

I am not at my wits end but this is were my mechanical ability and tools end, is there something else I can try or should I just strap up and take it to a local shop? (any recommendations would be great!)
 
do a compression test on all cylinders, if #4 is low you have valve issues

also listen for #4 injector to click or tink like all the others....best to check with a waveform meter but a screwdriver will work in a pinch

could be a pcm issue not sending signal to fire that injector
or
valve issues
or
???
time for a pro
 
A lot of times random misfire codes are from vacuum leak or timing issues but I’ve also had mass airflow sensors do this exact same thing cause it meters the air pressure and the computer makes adjustment to enrich or lean out fuel depending on air pressure going into engine.
When the MAF sensor fails it will give erratic signals and the ECU has trouble compensating for the irregularities causing misfires.
Some places sell the insert that goes into the MAF housing and they can save you money from buying the whole unit from the dealership, however, do your research as some are chinese knock off junk that are not calibrated for the engine they claim it fits.
Bosch has been pretty good with MAF inserts although I’m not sure if they make them for your Mopar.
 
Update!

I believe my issue is resolved, a mechanic friend volunteered to problem shoot my issues last Sunday. He said the 1st thing we were going to do was take off everything I had put on check out the parts and reinstalled (this was for his check list), after that we ran a compression test which came out fine and also check the vacuum system - air - and EVAP canister.

He scratched his head after we reset the computer and had the P0304 code pop up again with the truck starting up having the rough idol and an obvious misfire. Then we slammed an few beers and took a 2 hour break, he asked me if I gaped my plugs before installing them the 1st time. I told him they were pre-gaped so why should I, after cussing at me we pulled #4 and #6 plugs, and #4 was several milometers apart from #6.

End of Story and Lesson: We pulled every plug and gaped them by hand to factory recommended settings and the truck has by running well since Sunday. CHECK YOUR PLUG GAP!

Now I need new tires.
 
Update!

I believe my issue is resolved, a mechanic friend volunteered to problem shoot my issues last Sunday. He said the 1st thing we were going to do was take off everything I had put on check out the parts and reinstalled (this was for his check list), after that we ran a compression test which came out fine and also check the vacuum system - air - and EVAP canister.

He scratched his head after we reset the computer and had the P0304 code pop up again with the truck starting up having the rough idol and an obvious misfire. Then we slammed an few beers and took a 2 hour break, he asked me if I gaped my plugs before installing them the 1st time. I told him they were pre-gaped so why should I, after cussing at me we pulled #4 and #6 plugs, and #4 was several milometers apart from #6.

End of Story and Lesson: We pulled every plug and gaped them by hand to factory recommended settings and the truck has by running well since Sunday. CHECK YOUR PLUG GAP!

Now I need new tires.
Glad you figured it out. Plugs come pre-gapped like you said but unfortunately you have to double check every product you buy for quality. A cheap, easy fix this time. You got lucky!
 
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