Hello,

last week my 2010 XF started missing noticeably, and I connected the ODB2 reader to find a Cylinder 8 misfire. I swapped the plugs in cylinders 8 and 6, ran it for a few minutes, and observed the cylinder 8 missing code (P0308) still. . I went to AA, bought an ignition coil, installed on cylinder 8 since the problem appeared to stay with the coil and not follow the plug. Car started, ran great, cleared code, test run around the block, all is well.. shut off. That was two days ago in the warm afternoon high 70's (in case temp is a factor). This morning (high 50's) started it, and it was not idling good at all. Engine light came back and now I have a cylinder 6 and 8 misfire (P0306 & P0308 codes) along with code C342D (Manufacturer Control) . I'm considering replacing the spark plugs just for the heck of it, not sure what do right now.... researching.....

 

I "guess" you have the 5.0L engine? SC or NA?
How many miles does it have? Have the plugs/coils/injectors been replaced before?

These DI engines have lot's of injector problems and I would leaning in that direction.
Not much on that C code so can't help with that one.
.
.
.

 

Hello, it's a 4.2-liter V8 engine, Not the 5.0. sorry for not specifying that. I was looking through receipts today... I can't remember but i don't believe I've every replaced them in this car and I can't find the receipt for added evidence.. It's at about 65k miles. I bought it with 34k in 2017.

 

Sorry about that and yes ignore what I said as I was thinking of the 5.0 engine. Yes the 4.2 usually has far more coil and plug problems rather than the injectors but time has gone on and with age and use anything will wear and fail.

Be aware of after market and/or counterfeit parts to. Try to stick with OEM if you can.
Are you clearing the codes after reading them? That odd C code might just disappear when the other problems are fixed. As you said it's a rare and the description (Manufacturer Control) is of no help as I don't know what that is?
.
.
.