Misfire please help

[boybadone]

Hi guys, I have a 2004 yukon with a 4.8. My check engine light is on and the code is P0302 (cylinder 2 misfire). The light will illuminate intermittently and sometimes is flashing.

I have replaced the spark plug and swapped both the coil and wire. So unless the coil is not receiving a signal I imagine my condition is not spark related?

Where do I go from here? Should I swap the fuel injector as well?

Any help would be much appreciated, thanks!

 

[scrtcell]

Misfire

Yes I would swap the injector but first check wiring to the coil and to the injector....

 

[boybadone]

thanks

how do i check the wiring?

 

[boybadone]

Does anyone know where I can find a tutorial or even explain how to check the wiring to the coil and injector? I can't find anything.

 

[ccapehartusarmyINF.(ret)]

do you know how to use a multi meter
i cant remember exaclty what it looks like usually there is a terminal and you should be able to get a positive probe in there some where and if yer meter reads in the neighborhood of 12 volts then yer connections good less then that or no reading you got a short or its grounding out or highresitance
oh make sure the car is running
same thing with the injector theres a harness or terminal that plugs in to the injector unplug the suspect one and check to see if its getting voltage if all that checks out
id start going thru the fuel system starting with the fuel rail
oh and make sure yer batterys good probably not the issue but ive seen a bad battery cause so many wierd symptoms

 

[boybadone]

Thank you chris. Unfortunately, i gave up and brought it to the mechanic. I will update this thread when he finds the problem.

---------- Post added at 02:36 PM ---------- Previous post was at 12:59 PM ----------

So I just spoke with the tech and it does not look good. The ignition is good, the injector is firing but cylinder 2 is slightly low on compression. He thinks it maybe a broken valve spring.