I have a 2007 3.6 CTS with about 78k. The other day I was accelerating to merge onto the interstate and the car jerked a couple times. The CEL flashed a couple times also. The jerking has been slowly getting worse over the last few months. It is pretty random when the car jerks, but each time the car jerks the RPMs drop slightly. I went to Auto Zone and checked the error code. I had two error codes that both read cylider 4 misfire.

I've been cruising the forums for awhile now and it seems like the problem is likely spark plugs coils, or maybe a couple other things.

My question: What do you recommend I replace first and could I do it myself?

Any input is really appreciated!

 

what r the codes
p0300
p0304
to check the plugs quick -just flip them with another one misfire should move if so replace spark plug

do the same with the wire
do one step at a time
dont do spark plug and wire at the same time one then the other
but u must scan and clear codes