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Discussion Starter · #1 ·
2010 Ram 1500 4x4 Big Horn, Hemi, 27k miles, bone stock as from factory

The dealer had my truck for several days due to a check engine light and misfiring. Last Friday they said it was just 1 cylinder misfiring and when they moved that injector to another cylinder the misfire followed the injector. So they checked all the injectors and determined that one was bad and another was iffy so they were going to order parts and replace them.

Then the story changed...

So I called them yesterday to see if the truck was ready and they told me it turned out the injectors were fine, rather it was carbon build up on the valves disrupting the air/fuel mixture. They said it was probably due to bad gas. They said they flushed it with some de-carboning whatever and I was good to go.

Now what's wrong with that story...did the carbon build up on the valves just magically jump to the other cylinder when they previously moved the injector and the misfiring followed the injector to the other cylinder? Sounds fishy to me, about as fishy as the "bad gas and we can't control that" excuse. Bad gas really, then why is it just 1 cylinder misfiring?

So...instead of replacing the 2 injectors they said Chrysler decided to instead de-carbon the valves. So they decarboned them and apparently the 1st round didn't get rid of the misfire but they could watch it change. So they decarboned it a 2nd time and said that fixed it and I was good to go.

So I called BS on that entirely over the phone. The service staff had all left by the time I got there, I started the truck and it was still misfiring boy what a surprise. No check engine light so I drove it home. The next morning I didn't even make it out of the driveway when the check engine light came back on.

So its not plugs (they did replace them) its not the coil, its not the injectors (highly supsect imo), and they de-carboned it twice. So what's left if its carbon fouling, that just leaves the valve stem seals. They already did a compression test and said compression was fine so the valves, seats, rings appear to be good. The thing is with 2 plugs per cylinder and fuel injection man how does that even misfire it would have to be smoking pretty bad I would think.
 

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my guess would be injectors first. I doubt you could have a valve seal go bad this quick. There are always the random occurances, but man thats sketchy.

A bad injector could in theory cause carbon build up dumping in so much gas all the time the plugs just cant handle it. Did they say what cylinder it was?

Check your CEL codes and see what cylinder is saying its misfiring and pull the plugs and see if they are just soaked in gas/oil/look like crap.
 

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Discussion Starter · #3 ·
They said it was cylinder #2 or #3 I don't remember which but it was one of those. I agree with you regarding the seals, low probability and no oil smoke out the tail pipe and doesn't smell like burnt oil. I'm with you its got to be the injector(s) I said that from day one only the new story is supposedly they tested them and they are fine which makes no sense. If the injector was fine the miss would not have followed the injector, period.

I don't know why Chrysler would resist just replacing the injectors, its got to be cheaper than paying the dealer to wrench on it for days. I'm hoping its the injectors to be honest, if its valve seats, seals, rings, or their funky fuel saving lifters or something I would be thinking of trading this off before the powertrain warranty runs out for sure. The dealer said they get a LOT of local law enforcement cars with this engine in for valve seat issues.
 

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No way it's carbon build up. I've pulled engines apart with 150k+ miles on them and there hasn't been enough carbon to cause any misfiring. They're grasping at strays right now I'd say.
 

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Here is the bottom line.

They moved injector #1, to the second or 3rd cylinder. Then when they started it, the misfire was on cylinder 2 (or 3).

=Replace bad injector. Any technician worth his weight in crap will tell you that.

You valve seals are not bad, you would have smoke, even from one bad one. Your compression is good. But dont drive it anymore, or it wont be. If the injector is stuck in the open position (spraying fuel constantly), its washing out your cylinder. This means there will be little/no oil on the cylinder walls, which will burn up your ring and score your sleeve/wall/piston. Best bet is to call a different dealer and have it towed, even if you have to pay for it. By driving with the misfire undiagnosed, you could be doing irreparable harm to your engine.

I am with GearHd6, I have torn down engines with over half a million miles, and NONE have had carbon buildup on the head/valves/piston or combustion chambers significant enough to cause a misfire. That's alot of facking carbon.
 
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