P0308 Code

[21 Blue Ram]

Hi,
I have a 2021 Ram 1500 with the Hemi, that I bought used about 1.5 years ago. It had 26k on it when I bought it. Has just under 40k now. Have noticed a few times upon starting a loud tapping noise, that quiets down after about 10 seconds. Today when I started it, it was running a bit rough. Started to drive down street and got start/stop system shut off message and then check engine light came on, so I went back home. Check engine light was flashing. I have a basic code reader and it came up with P0308 code- misfire in cylinder 8. Going to call tomorrow and try to get it into a shop. Hoping it’s something minor like plug, coil, or injector, but worried it could be the lifter issue. I did purchase an extended warranty, not a Mopar one. Just looking for input as to what others have run into. I run 5W20 Royal Purple full synthetic oil in it. Thanks.

 

[Fatherof3]

I’m not an expert but I don’t think it’s a lifter issue . The tapping noise wouldn’t go away if it was .

 

[21 Blue Ram]

Thanks. Was able to bring it to my mechanic today. Fingers crossed nothing major.

 

[John Kloehr]

Agree "the tick" would not stop after a few seconds. And it is at a mechanic so the rest will not help you.

With the low years and miles, not anywhere needing plugs. Could be a failed coil. Swapping it with another coil to see if the problem moves would be an easy diagnostic.

First I would hook up my handy-dandy OBD diagnostic tool and look at the fuel trims for that bank. If it is a failed coil, then there will be too much fuel in that bank and I would expect the PCM to reduce fuel to bring the A/F ratio back in line. Would also listen to the injector with an automotive stethoscope to see if it is activating. And if it is not or if it is clogged, then the PCM would add fuel to compensate.

Another possible problem accounting for the tick at startup would be a broken exhaust manifold stud or cracked manifold, kind of common on these trucks. The leak may tighten up as the manifold heats which would account for it fading after start. A leak here would dilute the exhaust gasses and the O2 sensors would see this as a lean condition. The PCM would add fuel. This would make the cats happier but the engine would actually be rich. This could foul a plugs (or more than one). Visual inspection and the previously mentioned automotive stethoscope can help with finding the source, and removing the plugs to inspect them for soot would be part of the diagnostic procedure (along with looking at the fuel trim). If they are heavily sooted, then they might need early replacement; I have had mixed results cleaning these modern plugs.

There are a few other things it could be (massive intake leak at #8, ...), I tried to hit the common and straightforward likely suspects. I would have still expected at least pending codes for rich or lean conditions in addition to the misfire on 8 so scratching my head a bit on the one. Please post up what your mechanic finds.

In any event, a flashing CEL is a stop-driving signal as there could be expensive damage soon. It this case, it would probably be damaging a catalytic converter. So getting it to a mechanic quickly is a correct action.

 

[1791]

same issue lifter noise for about 3 seconds i'm told it's normal and it won't hurt anything. still the sound is troubling

 

[Bearsworld]

Hello Forum members,
Bearsworld here.
2019 Ram 116,000 miles roughly, just had oil pan and right side exhaust manifold replaced at dealership in October and of course an oil change.
I have not changed the plugs as of yet, or checked the coil packs but I am having the dreaded p0308 cylinder # 8 misfire code now again.
After exhaust manifold was replaced the engine was quiet as a mouse. No ticking at startup anymore and also no more slight oil leak ( oil pan was rusting badly and my 2010 did the very same thing ) and I had some slight seepage from the oil pan ( so far being a 2019 living it’s entire life in the North Country of NY near Watertown,NY the oil pan was the ONLY place on this truck that rusted ), my 2010 was severely rusted around 125,000 and I kept it till just over 180,000 miles and ZERO misfire codes with 120,000+ miles on the plugs ( head gaskets failed just before 60,000 miles and fixed including new plugs then.
This truck will around 5-7,000 miles I am thinking at Idle ONLY throw the p0308 code 650-680rpm engine warm, ZERO noises and no misfire felt or heard.
As it is now winter in our area and we are expecting .3-.5 inches of ice/freezing rain tonight that has already started and Winter Storm Warning from tomorrow afternoon through Saturday now I believe for Lake Effect Snow of 1’-2’ feet or more depending on strength and direction of the up to 50mph winds also part of the Warning I cannot check coil pack or plug for Cylinder #8.
Again, it ONLY triggers this code at idle have any of you experienced this particular p0308 event and what did you do to fix it.
Also, beyond checking spark plug and coil pack any other suggestions to look at?
I am going to try this week to get it scanned with a much better scanner than I have presently.

 

[Rebob0510]

Bearsworld: Syracuse, NY here... not looking forward to this weather we are getting. My truck had that same issue around 8,000 miles ago, would idle kinda rough and then I got a check engine light for it. I started by moving #2 coil to #4, still had the same misfire in 2, I bought 2 new plugs and still had the code. I have a AFE cold air intake with a oiled filter, I went to clean the MAF sensor only to realize that they don't use them on dodge, I did some research and I found that a dirty IAC (intake air charge) sensor could cause a misfire, I went to advance auto parts and got a new one for like $25, changed it in about 18 seconds and the truck idles much smoother and the check engine light has been out for over 7000 miles. The IAC sensor that came out was nice and blue on the back side but black on the side the air hits it at, i think the oil from the AFE filter did it, I switched over to a dry element after that

 

[Cbty2050]

Also, beyond checking spark plug and coil pack any other suggestions to look at?

Fuel injectors are common