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Discussion Starter · #1 ·
Okay.....so I have a 2012 Charger R/T when I bought the car it had a bad lifter on cylinder 3. So I replaced all lifters, cam, timing set, head gaskets, oil pump, valve seals, spark plugs, and coil packs.

Now I have a missfire only at idle on cylinder 4. After it warms up. Cold start no miss. I've swapped around the injector and no change. I did compression and got 90-120. Car runs like a scalded dog. No hesitation. Just a missfire.

Any input is appreciated.

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2013 R/T
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Curious what brand valve seals did you use?
Does it only toss the code when ran hard? Just a CEL or does it run rough and clear up?

Pull your plugs soon when its misfired.

If you have glazing candy coated insulators and oily threads, smoke puffs on random startups it could be just a stem seal.
I had some Felpro stem seals pop off the lands. Others have reported same.

I have a supercharger so I'm not sure if it matters since mine were on when a couple WOT runs were made.

Clear Glazed, it did not run rough, just a code toss. CEL illuminated and went out. Fresh oil change.
Oil on threads. Not in valve cover access bore. It looks wet like you can clean it off but for get about it. Diamond hard
Grille Automotive lighting Motor vehicle Automotive tire Hood


Same as above but this was after several WOT runs.
Tossed code, ran rough, light stayed on. Oil on threads. Hard kiln like baked on. Oil on threads.
Automotive tire Gas Engineering Auto part Cameras & optics


Found Fail-Pro Valve stem seals popped off their posts.
Gas Automotive tire Coil Auto part Engineering


New CompCams p/n 531-16 seals on, never a smoke puff on startups, none, no miss-fires, no oil on threads, plugs look good.. Good luck.
 

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Discussion Starter · #3 ·
Okay.....so I have a 2012 Charger R/T when I bought the car it had a bad lifter on cylinder 3. So I replaced all lifters, cam, timing set, head gaskets, oil pump, valve seals, spark plugs, and coil packs.

Now I have a missfire only at idle on cylinder 4. After it warms up. Cold start no miss. I've swapped around the injector and no change. I did compression and got 90-120. Car runs like a scalded dog. No hesitation. Just a missfire.

Any input is appreciated.

Sent from my moto g power using Tapatalk
 

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Discussion Starter · #4 ·
Okay.....so I have a 2012 Charger R/T when I bought the car it had a bad lifter on cylinder 3. So I replaced all lifters, cam, timing set, head gaskets, oil pump, valve seals, spark plugs, and coil packs.

Now I have a missfire only at idle on cylinder 4. After it warms up. Cold start no miss. I've swapped around the injector and no change. I did compression and got 90-120. Car runs like a scalded dog. No hesitation. Just a missfire.

Any input is appreciated.
 

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Have you checked for DTCs with an advanced scantool that can read Pending, Powertrain, Chassis and Body codes?
 

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Did you go MDS cam and lifters, or Non MDS cam and Lifters, or mix match?
 

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Discussion Starter · #7 ·
No glazing. No smoke. And I used Mopar valve seals. It runs fine. But shakes at idle. As if cylinder 4 is a dead miss. Raise the rpm to just above idle and it's fine. WOT it runs strong, has no hesitation. We decided to drive it 460 miles one way to a basketball tournament. I'm currently sitting in the parking lot of the hotel with my scanner pulling codes......

P2097 Downstream Fuel trim system 1 Rich (Pending)
P0304 Cylinder 4 Misfire (Active)
 

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Discussion Starter · #9 ·
Only codes currently are Misfire cylinder 4 and system rich downstream bank 1. But like I said it only misfires at idle.
 

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I would look at swapping coils see if misfire follows as an easy first step. Look at cyl 4 plugs. Check Gap. Then maybe an injector.

Check wiring as well.
 

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Discussion Starter · #11 ·
Did all that. I've replaced all plugs and coil packs, and then swapped them around and swapped the injector with another. No change. Still misfire on cylinder 4 at idle.

We just got back from a trip in the car that was 740 miles total. No change in the code. Car runs fine. Just misfire at idle. Don't understand.
 

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Did all that. I've replaced all plugs and coil packs, and then swapped them around and swapped the injector with another. No change. Still misfire on cylinder 4 at idle.

We just got back from a trip in the car that was 740 miles total. No change in the code. Car runs fine. Just misfire at idle. Don't understand.
Only thing I can think of now is to pull a valve cover and see if the rocker arms have same throw while running as others. The rich condition leaves me to believe combustion just is not taking place at all vs partial.

Can you get photo of the plugs?
 

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At some point DIY doesn't cut it... take it to a service center for an assessment.
 

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At some point DIY doesn't cut it... take it to a service center for an assessment.
Dude's got a 1000 dollar scan tool he is probably a little beyond shade tree mechanic status and he's alredy done all the little shit that they might do for an assessment before charging 150 bucks an hour to do something he's already done before if you don't have anything useful to add then stfu. that being said my money is on the valve seals
 

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MC:
That compression reading of 90-120 sounds a bit low to me. When you had the heads off, did you have a machine shop go over them and freshen them up? There may be some minor collateral damage from when the lifter(s) ate the cam.
What was the mileage when the lifter/cam issue presented?

Don
 
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