Hi Richard,I think that the answers given above are the ones you can follow. It is possible that you have a defective plug on that particular cylinder? even new plugs can be defective. You should also check and make sure that the cam in the distributor is not bent or that the bushing is not worn (unlikely but possible). You can do this with a feeler gauge, measuring between the the rotor blades and the pickup coil. I'm afraid though that you may have a ECU (Electronic Control Unit or Computer management System) problem, in which case, your best bet is to replace the unit.If you can borrow a unit from a friend with the same vehicle and test first, that will be your best bet.Regards Johngee10
Do a compression test on that cylinder to make sure that you don't have any leaks that could be contaminating which could be leading to the misfire.
One other thing to check while you have the injector unplugged is the injector coil resistance. Compare it with a couple of other injectors; if it is substantially lower the coil has a shorted winding and may not generate enough of a magnetic field to open the valve consistently (I've seen this on GM injectors - the symptoms were the same as what you describe). Prolonged operation with a shorted winding can ruin the injector driver transistor in the engine computer. If the coil reads open or much larger than the other injectors, the coil is broken or burned out - this won't hurt the computer, but it certainly won't work.
One note on David Levy's solution (nice write-up, by the way) - one of the injector wires is connected to 12 Volts through the ignition power circuit and the other is switched to ground by the computer to pulse the injector. You won't see voltage on the switched wire unless the connector is attached to the injector when you measure and the coil is not broken.
Hello Richard,
Thank you for requesting my input on this issue.
Please do not touch the crank sensor (unless you have obtained the correct code for this component).
So far, David Levy's solution is concise and thorough - I recommend you follow through with David on this one, as he is providing your with a correct systematic approach. This will also avoid any unnecessary expense on your part.
Good luck.
Scott
The crank sensor cannot be the problem, based on your symptoms the code p0304 means misfire cyl 4 , it's sounds to me like you may have a notorious mopar computer issue...there are things you need to check first
identify fuel injector #4 it should be tagged on the harness, put your test light lead to ground and check both injector wires for power once you flip the key on if there is no voltage you will have to check the harness...if there is voltage then you will need a noid light 5-7.00 at parts store ,plug it in to your inector harness connector start the truck and see if the light flashes , since you say it is only or mostly present at higher rpm acelerate the engine and see if it drops the "pulse" next you will have to check resistence in the harness (ohms) if you get to that point let me know and we will go from there... by the way most failiures of the crank sensor with the 5.9 are no start conditions you would have no spark..also are there any other codes
the crank sensor cannot be the problem, based on your symptoms the code p0304 means misfire cyl 4 , it's sounds to me like you may have a notorious mopar computer issue...there are things you need to check first
identify fuel injector #4 it should be tagged on the harness, put your test light lead to ground and check both injector wires for power once you flip the key on if there is no voltage you will have to check the harness...if there is voltage then you will need a noid light 5-7.00 at parts store ,plug it in to your inector harness connector start the truck and see if the light flashes , since you say it is only or mostly present at higher rpm acelerate the engine and see if it drops the "pulse" next you will have to check resistence in the harness (ohms) if you get to that point let me know and we will go from there... by the way most failiures of the crank sensor with the 5.9 are no start conditions you would have no spark..also are there any other codes
David I checked the#4 injector with a home made led noid light there is an intermittent misfire. The resistance of all the injectors are the same .015 as I bring the rpm up at about 44-45 hundred it does the same thing bucks and jumps the light doesn't always come on at that point maybe the second or third time I do that it comes on I have reset the code and driven around the block a couple of times and the engine light doesn't come on usually by the time I make a trip 10 miles or so and stop the truck and restart it comes on.
Dave.. the light above is the check engine light not the noid it the noid light works fine at low rpm but is intermittent at 44-45 rpm. I will try to be clear on the problem because I really need some sound advise. This is my first time to use this site and I am really struggling to respond to you and thinks for any help.... you have already been a big help by letting me know it wasn't the crankshaft sensor.
I was confused but now I understand......ok so it sounds like you are losing signal from the computer, what I want you to do is with the key off disconnet the three plugs from the computer as they are of poor design they get contaminated ,clean the plugs (harness side) with a contact cleaner wait for them to dry and plug them back in , you can disconnect the battery if you want beforehand however in this truck it is only necessary to have the ignition switch off , try to run it and see if it corrects the problem another quick way I found over the years to help me identify a bad computer in a Chrysler prod is to run the engine and wiggle the connectors at the computer to see if there is any change in the way the engine runs ...what this indicates is that the solder joints on the internals are weakened the next step I would take is to ohm the injecter wire to the PCM I will comment the location and pin # to you tomorrow btw checking compression is always a good idea however I am assuming that since the problem is at higher rpms that it is electrical . Those engines 5.9 5.2 4.7 known for compression issues btw where are you If you don't mind?
ignition power feed to the injector is darg green wire with orange tracer, signal wire is light blue with brown tracer
it is populated in connector 2 (white) pin 16 ohm the lt blu wire
The computer in that truck should have security and is vin specific I don't think it's a good idea
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Random/Multiple Cylinder Misfire Detected have a good day !!
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are u in park when the misfire occurs
Why would you suspect the crankshaft position sensor? That would likely not be the problem.
i was in park when the back fire and rough idle occurred but the light comes on when driving
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