2012 Misfire, Blinking CE Light and other fun anomolies

[yoda]

As mentioned a blinking CEL indicates a misfire. They do not always set a misfire code if it does not miss long enough.
Based on your description i would pull the valve cover passenger side, inspect for broken valve spring on #4. Then have someone bar over the engine and measure valve lift on #4.
I have had a few hemis with worn cam lobes that don't make a lot of noise, they run fine at low rpm and load. Miss at high rpm and load.

I would do this after I road tested with a scan tool, verified what cylinder is missing, swapped plus, coils, and injectors to different cylinders to eliminate them.

 

[Demon-HeMi]

That’s not 100% true. It all depends what on the criteria for a dtc being set, some dtcs take one failure and a code will be stored even if that fault is no longer active. Others may take several trips before the dtc is set. There’s also seperate criteria for turning off the CEL and for clearing the dtc. Once again depends on the code, but there are set criteria that has to be met and the CEL will be turned off, then more criteria has to be met before the dtc will actually clear on its own.

If his CEL has been flashing on regular basis there will be stored dtc. You also need a scan tool that can read stored,pending dtcs, not just active ones.

yeah thats pretty much a longer version of what i said, i was assuming his CEL was turning back off, if it turns off it will typically clear most codes after a few full safe complete cycles where the fault doesnt happen anymore, i had a few TB issues a long time ago and misfire codes on one of my trucks and alot of times the code would disappear before i got home so i had to start carrying my reader with me

 

[irsmun]

Had the code read. Same as before. Misfire on cylinder 4. But this time an additional code came up: intake air temp sensor.

Not sure how, or if, that changes things. I am now going to focus on cylinder 4.

 

[irsmun]

I have had a few hemis with worn cam lobes

That is exactly what happened with my 09. It wore the cam lobe down to a nub. I spent $7000 in repairs before it went away. I had to get a new short block for it to correct.

This one is driving differently though. There is a jerking in the acceleration. Its not smooth.

 

[Pa.hemi.ram]

plugs...

 

[Dodge4x4810]

I do this all day long. Rule of advise, do the easiest first. The first thing I would do is check for codes, you said they clear, so if possible use a scanner and monitor the engine as you drive. I would start with pulling a plug on cylinder 4 (which you said was skipping), if the plug looks ok, i would do a compression test (instead of pulling a valve cover), just because it is much less time consuming. Then, I would do a compression test on a few other cylinders (easiest to access) to compare the readings. Going by the amount of miles on your truck, if it is not a plug problem, i'm leaning towards a mechanical problem.