2014 F-150 5.0L Misfire?

Messages
1,322
Location
Central Oklahoma
This is not my personal vehicle, but I thought I would share. My current rental seems to be misfiring. I picked it up with 3,300 on the odometer, and now has 4,100. At first I thought someone put bad gas in it, but after two tanks of 87 E-0, it still misfires. No CEL. Is this common? I've rented '13 and '14 F-150s before, all with the 5.0L, but never a misfire.
 
Messages
15,629
Location
Santa Barbara, CA
I swear there is a misfire at idle on my Mustang with the 5.0. There are no codes present, and I hooked up an IDS at work and nothing shows. Gas mileage dropped to 14.3, but some of that might be me slamming the loud pedal with the new exhaust.
 

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Messages
46,229
Location
Ontario, Canada
Originally Posted By: bdcardinal
I swear there is a misfire at idle on my Mustang with the 5.0. There are no codes present, and I hooked up an IDS at work and nothing shows. Gas mileage dropped to 14.3, but some of that might be me slamming the loud pedal with the new exhaust.
If it is anything like the older Ford stuff, they won't tag a misfire until you have like thousands of them. I went through that with the Expedition which, IIRC, has NEVER had a CEL for what are obvious misfires. You can see the counts using the Mode 6 data though, which is what I did, and then replaced the coil with the obviously high misfire count. Problem solved.
 
Messages
17
Location
New Orleans
There is a big issue with the Eco shuttering and misfiring due to what some people think is caused by the PCV systems. The only issue I have heard about the 5.0L is a little rough idle. This was due to spark plug gaps not being set correctly from Ford. It was really only a issue with the 11-12s, 13+ they seam to get it straight. I have a tune on mine and currently at 22K miles. My tuner asked me to double check gaps just as a precaution, I plan to do so at 25K. Wayne
 
Messages
182
Location
Michigan
I have read on anothr forum tha a few people have had problems with sensitivity to plug gap on these motors They usually end up putting new plugs in, gapped to the proper gap, to cure the mis-fire.
 
Messages
3,299
Location
West Michigan
On the Coyote engines I have found they don't always throw a misfire CEL if they are misfiring, there is a threshold. This is compounded by the fact the PCM will actually deactivate a cylinder momentarily if the misfire count exceeds a certain level (which seems to be below the misfire CEL threshold). To look for misfires you need a scantool capable of pulling mode $06 data which will give you misfire counts for each cylinder over the last 1000? rpms. I found on my '11 I was misfiring pretty badly coming off the line at on highway cruising speeds. No CEL, low-end of normal fuel economy. Mode $06 showed low level random misfires with frequent misses on #8, COPs looked good, no power loss but when I pulled the plugs there were all significantly over gapped (which is apparently a common issue on these motors). Autolite had a heavy rebate at the time so instead of regapping I replaced with Autolite Iridiums which brought my mode $06 data to basically zero. I believe I have a thread or two on these forums about this issue, if you want to search. The plugs weren't the only issue and I've seen some improvement with a MAF cleaning. Fuel injector cleaners (unsurprisingly) didn't help. Problem has pretty much gone away, but not 100%. I suspect the PCM has something to do with it, and perhaps there is a driveline harmonic issue but at this point the symptoms are only barely noticeable and only occasionally. edit: Also, if this is the longer wheelbase with the two piece driveshaft that opens up a whole new can of worms and you could very well not have any engine troubles at all. Those ARE known for driveline issues including sticky driveshaft splines and pinion angle induced vibrations on take off (caused by long anfd soft leaf springs "wrapping") and a few other things. Ford has deemed these problems "normal."
 
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