Cylinder #1 misfire.....but only at 4500/5000 rpm

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socalluke
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Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by socalluke » Mon Jan 21, 2019 7:11 pm

New here, and of course need some help. My searches haven't popped up with the same scenario. So I thought I'd ask the experts here:

Have 2012 RAM Power Wagon with 5.7 Hemi in it, with 92k miles and have owned it since 8k miles.

Late Dec. While towing, I had a blow out (going up hill) on one of the 4 trailler tires and dragging the blown tire cause an increased load on the engine, and the RPM went sky high until I was able to pull over, less than a mile. (I was in Tow/Haul mode.)

As this was happening the check engine light came on, was flashing, and began beeping. The radio, was on, but I also think the engine died when I came to a stop, (but not 100% sure.)

Changed the trailer tire, popped the hood. Oil level was fine and all temps (coolant, oil, transmission) were all fine. So I limped along without straining the engine and checked the code at the next AutoZone. It was P0301.

Ended up finishing the trip and as long as I kep the rpm under 4500 rpm the truck drove fine. Even wheeled it a bit. Then drove home. It was only when downshifting or going up an incline, and going over 4500 rpm which would cause the CEL to flash and beep. Then once the rpm's dropped the light would go solid.

Got home (whether with a trailer or not, whenever I hit 4500rpm would cause the CEL to flash.) Mechanic verified the same code P0301 and replaced all spark plugs, coils, and air cleaner. No CEL light and it ran fine.

One week later, I was playing around with the tow haul mode, while driving on the freeway to see where it shifted. (I just moved from 34x11.5 tires to 35x12.5 and was curious.) Well this spirited driving in tow/haul mode caused the CEL to flash and beep. Slowed down, took it out of tow haul mode and then the light went solid. Kept the rpms down and it drives fine. Mechanic checked and the code was again P0301 and U1449. It was Friday afternoon, he looked at a few things but didn't take anything apart. And reset things.

Today I put it on the floor and watched the rpm climb, when it hit 5000rpm, sure enough the CEL began beeping and flashing. Drove normally, it went solid. Stopped and it went out didn't come back on.

Any guidance? or Suggestions?

Colibri
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Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by Colibri » Tue Jan 22, 2019 1:13 pm

Could be the beginning of cam/lifter trouble.
Central Texas and Houston area
2009 5.7 auto quadcab
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Howe steering pump and gear with hydraulic ram assist
Custom tube bumpers and white knuckle sliders
Creative fab trussed axle. rem polished and cryoed 5.13 gears with arb lockers fr/rr
Sharadon stage 2 545rfe with 3000 stall edge converter
Lots of other stuff lol

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Mule
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Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by Mule » Tue Jan 22, 2019 1:48 pm

Crank position sensor, maybe?

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Bill2014
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Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by Bill2014 » Tue Jan 22, 2019 2:42 pm

Did you happen to ask for all of the coils back after that dealer repair? :wink:
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Retired BLM Rig
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Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by Retired BLM Rig » Wed Jan 23, 2019 2:19 am

Could be cam/lifter issue, but I would try a fuel injector on the #1 cylinder first. It might be partially plugged or restricted somehow. It might be getting enough fuel flow at lower RPMs, but just can’t keep up at the higher rpm’s with the demands of wide open throttle. They’re easy to change in 30 minutes or less.

If you want to confirm first before buying, swap it with another injector and see if the misfire moves to that cylinder. If the code stays the same, you may be looking at a valve train issue on that cylinder.

Keep us posted. :patriot:

socalluke
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Model Year: 2012

Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by socalluke » Wed Jan 23, 2019 3:54 pm

UPDATE:
1. I did not ask for the coils back. Should have. Lesson learned.
2. Went to a different Mechanic, he performed vacuum test and all was normal at various rpms. Checked fuel injector voltage and it was right in the middle. They then drove the truck around with the code reader/scanner connected and noticed the U1449 would come on first, then the P0301. Perusing their technical service bulletin info they found, they found TSB 18-049-17 from May 16, 2017. Which says the PCM needs to be reprogrammed.

Going to the Dealer on Friday for two recall items. If they re-program the PCM and it works, I'll scan in my print out about it. For others to see.

Thanks guys.

Colibri
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Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by Colibri » Wed Jan 23, 2019 8:45 pm

Good luck sir, I really hope a simple reprogram takes care of your problem!
Central Texas and Houston area
2009 5.7 auto quadcab
Carli 3” coils deaver leafs 3” kings with 4 tube bypass rear and fr/rr hydro bumps
Howe steering pump and gear with hydraulic ram assist
Custom tube bumpers and white knuckle sliders
Creative fab trussed axle. rem polished and cryoed 5.13 gears with arb lockers fr/rr
Sharadon stage 2 545rfe with 3000 stall edge converter
Lots of other stuff lol

socalluke
Posts: 25
Joined: Mon Nov 24, 2014 8:43 pm
Model Year: 2012

Re: Cylinder #1 misfire.....but only at 4500/5000 rpm

Post by socalluke » Wed Feb 06, 2019 9:04 pm

UPDATE:
Long story super short. I have the dreaded cam/lifter issue on cylinder one. (Truck is now at a repair shop I trust, I can talk to the tech, sr. tech, and owner very easily and they are more than willing for me to stop by and take a look and show me things.)

Sure enough, they showed me how the top of the valve on Cylinder 1 doesn't move as much as the other valves.

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