I have tried searching the topics, but unable to find an answer. I have read about the 04-08 models having problems with the COP? I am only assuming, but here it goes. About a month or two ago, I started noticing that while idling, the enging would occasionally want to stall (it hasn't yet). It has progressively gotten worse, to the point that even while accelerating, I can feel a bad miss. This does not happen all of the time. There are times that it runs like new. I have been getting a CEL (with no codes)? Finally, this last time there were 2 codes. Bank 1 running lean, and cylinder 4 misfire. What are the COP's? Are they coils packs of some sort? My assumption is, that is the problem? Is there a way to actually test them? Maybe swap #4 with a different one and see if the misfire code appears on a different cylinder? I have just over 98K miles and have already changed the plugs and wires several months ago.

 

Coil on Plug which is a smart design in my opinion and many newer cars are switching over to this design.

http://news.carjunky.com/how_stuff_w...s_ic2315.shtml

A little bit of information for ya if you are interested.

Very smart diagnosing skills I like the way you think man. I think some people can honestly take a hint from this.

As far as my diagnosis goes I'm really interested in that lean code on bank 1. What all maintenance have you done on that truck involving fuel/air? I honestly think that code will be cleared by cleaning the MAF and TB, but don't quote me on that. Also if the COP test comes back alright then go ahead and try testing the fuel injector and see if injector and sensor are working properly. Usually sometimes with higher miles those damn things get gummed up but happens somewhat rarely. Finally if the injector is fine you may have a bigger problem such as a rocker arm, intake valve, or low compression. Of course that would be worse case scenario and remember always think what does an engine need to properly function?