Misfiring and can’t seem to find the problem on 4.7

rsancheztx220

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Okay so I have a problem with a code p0300 which i recently found out that cylinder #1#3#5#7 is misfiring but cylinder #2#4#6#8 is firing with no problems and can’t seem to find the problem. I replaced the spark plugs and recently just replaced the lifters and rocker arms but the spark plug change didn’t seem to do anything, both the coils and fuel injectors are getting power but it still seems to Misfire. I’m alittle lost on this one and can’t seem to find a answer’s anywhere on the web. even when I disconnect the coil and injectors one by one on the cylinder that are misfiring nothing seems to change but the cylinders that are not misfiring when I disconnect anything, there is a change of idle which I assumed those cylinder are firing correctly. any help is appreciated thanks.
 

RamRod37

2014 Ram 2500 HD 5.7 Hemi
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my first test would be a exhaust back pressure test on the bank misfiring sounding like stopped up catalytic converter. If there are no other codes but misfire that is where I would start cause 85% of the time that is what it will be if it has one on each bank.
 
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mrbigbill

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So, dodge 4.7s in that year had problems with micro cracks forming on the plug right where ceramic meets the metal base, I did read you changes plugs, I went through 3 sets myself, 1st 2 sets where from AutoZone and where champions, seems like AZ had some problems with a run of champions, try oriely or whatever you have and get a good set of plain non platinum NGK, both sets of champions cracked as soon as got to operating temp, hard to see but usually you'll see a small grey line in insulator right above where ceramic and metal base nut meet....the NGKs got about 20k on them before same thing ......also, worth a try and replace crank position sensor, using a scan tool mine was throwing wierd peaks only when one side of engine fires, new sensor cleaned up profile, but dime to a dollar plugs about every 20-30k
 

EdGs

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Check ground on that cylinder head. Long shot, but you never know.
 
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rsancheztx220

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I checked all grounds in the engine bay from the cylinder heads and to the engine block and they all them seemed good with no damage to them, and I also swapped coils from the side that’s not misfiring to the one that are and nothing happened i even installed two new coils on the side that is misfiring and still nothing , I installed autolites iridium xp and it seems to run better but cylinder #1#3#5#7 are still misfiring. I checked the wiring harness and there no damage or short anywhere everything is getting voltages the only things I’m think is that it might be a bad pcm but still not sure. everything so far looks good but still can’t seem to find a answer , I’m going to hook a scanner to read the data coming from both coils and injectors and see if I see anything odd. And I also check the valves seats and springs on the heads and they seem good and work correctly. I checked for vacuum leaks and there no leaks anywhere. Check Compression and everything is good . I’m still alittle puzzled on the situation.
 

pacofortacos

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Sorry, I see that you checked compression. Both banks identical.
Have you done anything with the cam or timing chain?

If there is a ground to the coils and injectors, the only things left on those is the wiring to the PCM and the PCM itself.
 
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pacofortacos

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hopefully these come through - from a 2001 dakota manual
 

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rsancheztx220

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I haven’t done anything to the cams or the timing chain I bought the truck from someone as is and haven’t done the timing yet but today I took off the valve covers to check the timing on the cylinder that is misfiring and the cam gear is one tooth off and is not at 12 o clock it’s at 11 o clock and everything else is timed correctly the other cam is at 12 o clock and cylinder #1 is at TDC at the 2 o clock position where it should be . I’m honestly thinking it could be that . since everything electrical is working correctly which I spend 3 hours checking everything from the fuse box to the harness itself.
 
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