Hey guys, My 9 COP died and all I noticed was rough idle after the engine warmed up. I know my truck pretty well after 260 K but I would have figured losing a cylinder would be much more noticeable. My code reader does not indicate which cylinder is misfiring, in fact it did not show anything wrong. Here is my question. Do they make a reasonably priced code reader that will pin point a bad COP, if so send me the model. thanks

 

A "code reader" isn't going to cut it. You need a tool that is capable of reading the Mode $06 misfire count data. Fortunately, an inexpensive ELM-327 OBDII/BT interface, an Android device, and a $5 app (Torque) is usually all it takes.

Note: Edited to correct the app's name...

 

Don't assume an entire COP assembly is bad.
You may just have a boot that has deteriorated and is arcing thru.
The coils last a lot longer than the boots/springs.
A bad boot can cause lots of misfires which can been seen in the data before a code gets set.
You also might just have a little moisture under the boot of the misfiring cylinder.

 

How do you know the #9 cop is bad?

 

Absolutely no spark from coil, installed new as I carry a spare and all is well. It is just a super pain in the **** to track this down. This is the first cop that has gone bad, but I have changed them out at each 75k service.

 

I had a COP go south on me earlier this spring. Driving to work, truck suddenly started running rough.

I have a Bluetooth OBD transmitter on board (as mentioned above), so I plugged it in, fired up Torque app on my phone and knew which cylinder was suspect within 5 minutes based on misfire count. Grabbed a new COP on my way home that very day and problem was resolved that evening. I consider the OBD transmitter and Torque app absolutely indispensable.

BTW, love the title of this thread.

 

Was the coil or the boot bad?
I've changed boots 3 times and still have original coils at 168k.

 

Good question. Unfortunately, I can't provide an answer. The COP/boot failed on a day when we were expecting a late snow storm and I absolutely needed the truck the next day. I didn't have the time available to do much troubleshooting. I just grabbed both boot and COP and threw them in. I know, I know...the ol' shotgun approach. Like I said, I needed the rig working 100 percent the next day.

 

Thanks for the input I am going to get the reader and the app, sounds way cool. I agree swapping out COPS ever 75 is probably overkill but gonna do it anyway with my maintenance schedule, I use the Motorcraft which come with boot and spring and I dielectric grease the hell out of them.