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Guys, I’m pulling my hair out with this misfire on cylinder 8 issue. I’ve had this truck less than a month and it’s been in two different shops trying to get this issue found and fixed. Here’s what has been done so far ( something’s twice) spark plugs changed, coil pack moved to another cylinder, checked valve train ( cam, lifters, and valve springs and all good), vacuum lines checked for leaks, the fuel injector have been moved to another cylinder as well. Usually the code repops within 50-70 miles. When they swapped the fuel injector I got almost 200 miles before it came back. The mechanic even put in some BG 44k. At this point I’ve spent about 500.00 to chase this issue.....I’m sure I’m not the only one to have this issue with a 150k 5.7 2013 Ram 1500. Any help or advice would be greatly appreciated.
 

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The P0308 trouble code means that the powertrain control module (PCM) has detected an issue with the ignition of the fuel being provided to cylinder 8. This must usually happen multiple times before a trouble code is stored

Some potential causes of the P0308 trouble code would include:

Faulty ignition parts such as the spark plugs, ignition coils, spark plug boots and wires, or distributors

Faulty fuel system parts such as the fuel pressure regulator, fuel injectors, or the EGR valve

A large vacuum leak

A faulty powertrain control module

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it is important to check for any and all possibilities before replacing parts. Most of the time a misdiagnosis will result from not taking the time to fully inspect and test every part of the system that has the issue.

https://www.yourmechanic.com/articl...e-cylinder-8-misfire-detected-by-andrew-quinn
 

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Thanks. I actually believe it is in the PCM/ECM as it hasn't been updated ever that I can tell and all the reading that I've been doing seems to point at that, but I don't think the fuel pressure regulator has been checked. My question is, would it not run rough or run abnormal if it wasn't getting enough fuel pressure? At least under medium to heavy throttle?
 

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Most common lately. (Im not saying that this is the problem because Im goin through it now myself)
Is there a design flaw in at least the fourth generation hemis where theyve moved the camshaft higher in the engine for better fuel to the cylinder. But in doin so theres not enough oil being splashed onto the camshaft at low rpms. Example: ideling. Or when running low speeds on 4 cylinders.
Many have had to replace the cam and rollers. Etc.
Ive bein playing around with mine for about 6 weeks. Changed all my ignition coils. Plugs. And still running the same with showing same code. But also now getting P2323.
I ordered a new pcm online rather yhan from dealer. It was only $187. Im going to give this a try and hoping that it fixes my issues
Preying its not my camshaft like so many others. I dont idle much or even run low rpms because I liveboutside of the coty. Its all or mostly highway driving for me.
I'll update here after I receive my pcm and hopefully it does the trick. I do have other accessories that are only working intermittently so Im hoping yhis is it.
Back to you soon
Oh. If amuone out there has more to offer me on this problem please msg me. Thank you
 

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Thanks. I actually believe it is in the PCM/ECM as it hasn't been updated ever that I can tell and all the reading that I've been doing seems to point at that, but I don't think the fuel pressure regulator has been checked. My question is, would it not run rough or run abnormal if it wasn't getting enough fuel pressure? At least under medium to heavy throttle?
This is what I'm waiting for. Ive ordered a new pcm. Keeping my fingers crossed that its not the dreaded camshaft problem that exists in 4th gen hemis
 

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I have a 2012 ram 1500 with 158000 miles with this same problem. I've thrown spark plugs and a coil at it. I've moved coils around. I finally took the truck in to service. They told me I have a rod knock that can only be heard using a stethoscope and that I should replace the engine.
 
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