Am new to this site and after reading many posts there seems to be some knowledge out there.

Have a 2011 Ram Hemi (223K) that has developed a part time miss on cylinder number 5. Replaced plugs & coil, compression is in line with other cylinders and there's no broken valve spring.

When you start the engine it runs great until you accelerate then it starts missing. Back off and drive easy it stops missing.

Thinking ECM, but certainly would appreciate any ideas you guys might share.

 

how do you know it's #5?

could it be a bad/dirty injector?

try having the BG products injector cleaning service

 

Thanks for your thoughts Dog. Repeatedly get code 305, plus removing No. 5 plug wire does not effect the engine. Fuel pressure is normal. Also bogs badly when accelerating. Maybe the next order of business should be an injector test.

 

Had a similar problem on #5. Getting it back with a new cam tomorrow.

 

Just replaced the camshaft on my '11. exact cylinder, same symptoms.

 

I might know tomorrow if I also have a bad camshaft as I go back to work on it then. Determined fuel pressure was dropping to 23 psi as the rpm's increased, new fuel pump module corrected that so now when it not missing it runs great. I replaced the ECM but that was a bad call, did not help. It seems to have intermittent voltage to the coil. Harness maybe.

Swapped injector out, saw no change. Rocker arms seem to have the same movement range as all others so the cam should be OK.

Automakers build good engines these days but I still don't like removing cyl heads in order to do valve train repair. Not sure I'm a fan of the MDS at this point.

Thanks for the comment.