wolf50

So I've had a 2013 f150 for about 6 months now. It's always had a random misfire when idling and sometimes when driving on the interstate. On the interstate its bad enough that it feels like the transmission slips pretty bad for about a second or so. I've had the cold start update done and I'm about to check the spark plug gaps. Any other ideas of what it could be or how to fix it?

No codes have been showing either and I've been checking pretty regularly with a bluetooth odb2 scanner

kydsid

Have you diagnosed this with anything to confirm misfire or just by feel?

HunterSmitty

Why are you describing it as a misfire when you have no evidence to suggest a misfire is present? A misfire is not a feeling. I have found in any F150 I've driven (5.0L or Ecoboost) that there are certain shift points that feel like a slip due to the torque converter and transmission figuring out what to do depending on throttle input. Not sure if it is the same as what you're describing.

wolf50

It doesn't happen often enough for me to worry too much about it but I commute 2 hrs daily so over a week it usually happens a few times. Haven't been able to catch it with my scanner when it misfires so I don't really have any basis to go by other than feel. It could just be normal for the truck and engine, my last truck was a powerstroke so I can't say I'm familiar with the way the new gas trucks run. When it does it at idle it feels similar to a cam loping but still pretty different. Sort of like a smooth idle then a pretty big sudden lope then back to smooth. I thought maybe this was just something to do with the programming or phasers until I noticed it on the interstate.

The reason why I say it's not the transmission or converter is because it does this at steady speed. Usually happens on the interstate driving about 65 or 70 mph, but that's just because that's generally the speed I drive. Doesn't matter if it's me or the cruise control maintaining the speed. Happens on flat ground and inclines, but it's not as noticeable on declines just because the truck is usually coasting more

bryan8252

My '11 does the same. Had it in the garage 3 times for it. Here is link to my thread about what I was told https://www.f150forum.com/f70/5-0-troubles-215464/. Bottom line: Ford said its normal for this engine.

wolf50

Just read your thread and thanks for the reply. It sounds exactly like mine, atleast I'm not the only one that's noticed this.

I'm going to try regapping the plugs today and I'll let you know if it makes any difference

wolf50

Well just re-gapped the plugs. 7 plugs were gapped at .055-.056 while 1 plug was at .052. Searching around a little bit, I found that Ford recommends the plugs to be gapped at .041-.047 for the 5.0.

I'll update once I drive around to see if this helped the problem at all

Kenferg1

You know, this plug gapping thing seems to be a common problem. Now maybe I'm naive, but I would think that a vehicle that is built to very specific tolerances would have properly gapped plugs installed at the factory. It isn't like the technology does not exist for the plug manufacturers to send properly gapped plugs to the factories. After all, Ford buys plugs by the millions. Someone at Ford needs to clamp down on these QC issues. I wonder how much they spend on warranty for such a preventable problem?

kbass24emtp

Probably not as much as you would think. Most dealers won't even check the plugs unless that parts changer light come on. My wife's Focus had a really rough idle and I had my dealer check it out and since the idiot light was not on and no codes, they did not check any further. They said it was fine. Now I checked the plugs and one was out of spec. I really need to check mine too but have not found the time yet to do so. I would be really shocked to see them in spec. Also for the guys with the out of spec plugs, what kind of MPGs were you guys seeing.

wolf50

The idle has smoothed out a noticeable amount and so far I haven't noticed the same miss that I had earlier. The real test will be driving to work this week though.

Before doing this, my truck was averaging 17.0 mpg over the past 11k miles. Its a scab with 4wd, 1.5 inch bilsteins in front, and 265/70/17 tires. I also haven't had the truck reprogrammed to adjust for the bigger tires yet since it came with 235/75/17s