I took my 2014 RAM 1500 slt 4x4 5.7 Hemi (150000 miles) to the dealer due to a cylinder 8 misfire. In Feb I changed all 16 spark plug and when the code originally started i changed the coil pack and pig tail. The dealership pulled the valve cover and said everything looked good. The compression on the cylinder is 155. They said the PCM was not sending a signal to the coil so they replaced and programmed. It is still misfiring and are stumped! Any ideas?

 

Find another dealer who is better equipped to deal with your issue.....

 

Swap the injector from that cylinder, with another one, see if the miss moves. Verify the PCM is actually firing that injector.

 

I have to agree with finding a different dealer or independent shop. Why the heck with the dealer jump to pulling the valve cover prior to confirming the coil was getting a pulse. They should start with the easy stuff and either rule it out or confirm it's part of the issue.

Is the only diagnostic code a P0308? What's the compression on the other 7 cylinders?

-Rod