P0302 Cyl. #2 Misfire...Stumped

Hello everyone! I am new to this forum, but constantly checked it in the past. My truck is a 2010 Ram with the 5.7L Hemi. I would also rate my mechanical skills at a 7/10, only because I don't frequently rip apart the internals of my engines constantly.

With that being said, I seem to be having an issue with my truck misfiring in cylinder #2. I only seem to notice the misfire when under load around 2700 RPM or higher (doesn't matter if on the road in gear or if parked and just revving the engine). If I drive the truck smoothly without any hard accelerations, I can usually not even notice the misfire. But whenever accelerating on an on-ramp or having the truck on cruise control, the misfire is quite apparent. It will usually flash the CEL and go into Limp mode until I back off for a few minutes, then the truck will run normally. Like in the post title, I do get a P0302 code for cylinder #2 misfire. That is the only code I get.

Here is a list of things that I have changed or checked:
- Changed all 16 plugs with OEM plugs. Also set the proper gap.
- Swapped ignition coil with cylinder #4...misfire did not follow to cylinder #4. Misfire still set in cylinder #2 after swapped ignition coils.
- Swapped fuel injectors between cylinders #2 and #4. Misfire still set off in cylinder #2.
- Compression test, 4 revolutions to get ~160psi in cylinder #4 and ~165 in cylinder #2. Seems to be within 10% and the values seem reasonable.
- Vacuum test to check for weak or stuck valves...~ 21 in Hg at idle and may vary very slightly and different RPMS. However, once the truck misfire and begins to set off flashing CEL, the vacuum moves down to ~15 in Hg. I'm assuming that the truck goes into Limp mode and adjusts the timing, causing the vehicle to have late timing...just a guess.
- After changing plugs, with only ~500 miles on the new plugs, the ends of the cylinder #2 plugs were a little black. The other plugs that I checked were white and cleaner looking. Maybe just a result of the misfire?

Sorry for the long post, but I am just stumped. I really am hoping that since the compression test and vacuum test looked alright, I'm praying my valve springs and camshaft is okay.

If anybody has any suggestions, I would greatly appreciate it! Thanks!

Try these per the Service Manual, P0302 cylinder #2 misfire code can have the following possible causes:
FUEL DELIVERY SYSTEM
IGNITION COIL WIRING, OR CONNECTORS
ECT SENSOR, WIRING, OR CONNECTORS
MAP SENSOR, WIRING, OR CONNECTORS
O2 SENSOR, WIRING, OR CONNECTORS
ENGINE MECHANICAL SYSTEM
POWERTRAIN CONTROL MODULE (PCM)

Sounds similar to this post here: http://www.ramforum.com/f44/p0307_headache_please_help-107735/

Maybe you can coordinate.

Yes, sounds like a very similar issue. Hopefully they reply back with a verdict on their problem.

Is there a possibility the coil isn't getting power?

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Golden cobra said:

Is there a possibility the coil isn't getting power?

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If the coil was getting power/ground you would get a separate code for that.

2010 Ram. 5.7, I would pull your valve cover. Spin the engine over and look at the valve springs. I can almost assure you that you have a bad cam lobe. You'll look for the valve spring that barely moves on that #2 cylinder. I can't even begin to tell you how many times I've had a cylinder misfire and I've had to put a cam and lifter set in. Especially on the 2010 Trucks.


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For anyone who comes and looks at this thread, the fix for my issue was a new camshaft and lifter. The cylinder #2 lifter seized up and stopped rotating, causing the lifter to grind on the camshaft lobe. This took the lobe completely down, causing my misfire issue.

Since the truck was out of warranty, I did the repair work myself. Took me a couple of weeks working nights after my day job, but the job wasn't all too difficult. Honestly, hardest part was removing the fan nut (which I ended up sawing off, because I was misinformed and found that some forums were incorrect, the thread is reverse of what you would normally do).

Is there any ticking coming from the engine? As mentioned it could be a bad lifter and cam lobe...

^^ times two

Glad to hear the problem was solved but, damn, a lifter seized?

DRobSForce said:

For anyone who comes and looks at this thread, the fix for my issue was a new camshaft and lifter. The cylinder #2 lifter seized up and stopped rotating, causing the lifter to grind on the camshaft lobe. This took the lobe completely down, causing my misfire issue.

Since the truck was out of warranty, I did the repair work myself. Took me a couple of weeks working nights after my day job, but the job wasn't all too difficult. Honestly, hardest part was removing the fan nut (which I ended up sawing off, because I was misinformed and found that some forums were incorrect, the thread is reverse of what you would normally do).

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You are a bad bad man, RF man of the week for sure. If by chance you can do an in depth write up that would be real helpful. Was getting the cam out easy?

Any pictures of the lifter and cam?

Great job.............

I will admit, performing the cam swap on this truck and engine was actually easier than I thought it would be. For me, it was just time consuming. But if I went back and did it again, it'd probably only take me 8 hours or so.

As for a write-up...I will see what I can do. I didn't take many photos throughout the process. I do however have the service manual (most of it) for the 2010 truck, which I acquired during my days at FCA. That helped tremendously.

Here are the photos of the bad camshaft and culprit lifter:

View media item 24910View media item 24908View media item 24909

Wow that's bad it's completely worn down. Looks like the cam wasn't hardened properly...

dude, was there any ticking/knocking prior to that? That is gross, **** happens way too often on these Hemi's.

Was that an intake or exhaust lifter?

Damn..!

I've heard that when engine is ticking or knocking, that's when it's slowly eating at the cam to make it look like this.

Is that statement true or we don't know?

Are lifters ticking just during their normal operation?

Hemi395 said:

Was that an intake or exhaust lifter?

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It was an intake lifter. I did a lot of diagnosing in hopes that it wasn't this problem. But I should've just pulled the cylinder head cover in the first place. You could see that the intake on cylinder # 2 was barely lifting when compared to the others.

Kap1 said:

Damn..!

I've heard that when engine is ticking or knocking, that's when it's slowly eating at the cam to make it look like this.

Is that statement true or we don't know?

Are lifters ticking just during their normal operation?

Click to expand...

Well I didn't have any noises that were alarming. There was a SLIGHTLY louder tick that started one day, but nothing that made me say shut it down for good until I find the issue. I only had the cylinder #2 misfire code and bogging down when under load/acceleration. It started out as a nuisance, only barely noticeable misfire. But now that I look back on it, it did get worse over time. I drove it for a month or so with the intermittent misfire. So that probably explains why the camshaft was gouged so badly. But after the replacement camshaft and all new lifters, everything runs well now.