For the past three years, or so, I feel like I've been chasing a ghost when it comes to a misfire. I have a 2016 KR 5.0 -- I'll experience rolling/rumbling misfires that'll make my truck shiver at idle only (never when driving). Sometimes it'll even make my truck stall out and go into that "low power mode" or whatever it's called, and I'll have to restart the truck to take off. It happens periodically, and it's not something I can willingly replicate. It could be once every couple months, or twice a month, or anywhere in between - and it'll run rough like that for maybe 1-2 days before returning to normal and run absolutely perfectly until it's next episode. Never a check engine light, so it's been a chore to try to figure out.

Things I've done in the last three years to chase it:

• Replaced spark plugs
• Replaced ignition coils
• Cleaned throttle body (twice)
• Changed vacuum check valve (though this was more to solve my IWE grinding issue)
• Most recently, this weekend, replaced my intake manifold -- while everything was apart I did my best to clean surfaces of fuel injectors, and cleaned build up around intakes

If anyone has other suggestions, by all means, I'm all ears at this point. But while searching for answers (yet again), I came across this comment on a YouTube video that kinda blew my mind. It just seems too simple ..
.After reading this, I thought - well I'll be damned. Because for the past three years I've been using MobileOne and sometimes a house brand synthetic blend from the garage down the street from my house. Who knows what brand that oil filter is. And, well, could that legitimately be the fix? Simply go back to Motocraft oil and filter? Has anyone heard anything like this before? Or seen the issue I'm talking about being caused by other brand oils and filters? What say you?

 

Well he also changed the VCT solenoids and I am 99% sure that is what probably fixed it. My old 2017 5.0 that my SIL has, has 95k and it has had nothing but Penzoil Platinum and Motorcraft oil filters and has zero issues whatsoever.

 

He stated in a follow up comment that he never touched his VCT solenoids, and all he did was take the recommendation to switch to Motorcraft oil and filter.

 

Intermittent VCT operation can indeed cause the issues you describe if the Cams are not moving back to Idle position. It affects cylinder compression pressures.
Someone with good diagnostic experience and a good hi end Scanner could have looked at the VCT operation and saw the miss-operation of Cam timing on their screen and live data to support it and know it was affecting Idle if they looked at it while the problem was present.
Changing oil to MC may have more Detergent additive in the oil formulation than the oil you been using. and has cleaned up the Solenoid operation.
Sometimes just using any other oil not specified for use by Ford , can bite you in the back end. Look on the Label for this notification..
These engines are far far from the old push rod engines of yesteryears and sensitive to Plugs, Oil conditions, Fuel quality etc..
Good luck.

 

Dealer told me same thing when I had misfire codes at 30k on driver’s side bank: Only use Motorcraft 5w-20 synth blend oil and filter, change oil at no longer than 5000 mile intervals. I’ve stuck to that interval religiously and have never had a problem since, now at 75k running strong. Additionally, I’ve been using the Liqui Moly Mo-S2 oil additive to control oil usage for last 2 oil changes (@Bluegrass recommendation ) and had great success with it. These 5.0L engines apparently need specific Motorcraft oils and care to run right.

 

It likely has less to do with Motorcraft products than the fact that the Motorcraft products are arguably "better" than what was previously being used. The Motorcraft semi-syn tests out as a pretty good oil. Pennzoil Platinum, Quaker State Full Synthetic, and Amsoil Signature Series oils would very likely yield the same results. I choose not to use Amsoil because I want an oil I can easily buy anywhere. I have only used the FL500S Motorcraft filter in my 3.5 eco because it is supposedly a good filter, available everywhere, at a good price.

My personal thought is that when using a top rated oil you don't need to change it more often than 5k miles. You are still "giving away" some oil life at that change interval, but to me it's better to err on the side of always having clean oil with a working additive package. Oil is pretty cheap compared to an engine component failure due to inadequate maintenance. Every one of us weighs their preference, makes their choice, and lives with the consequences.

​​​​​​Most people simply don't keep a vehicle long enough (very high quantity of accumulated miles or at least 10 years) to really notice the effects of inadequate maintenence.

 

Have read many articles about the need for Motorcraft oil and filter in Ford engines. In my opinion, the filter is the most important part of that equation. There are equivalent filters available but most people go with whatever looks OK and fits, probably cheaper. That is a mistake. The older 5.4 engines really needed the anti-drain back feature of the Motorcraft filters. Otherwise, they literally started dry or nearly starved of oil.

That being said. All I ever use is Motorcraft oil and filter. Along with a long list of Motorcraft only replacement parts particularly anything ignition related.

 

I agree that the most important item in this equation is the oil filter. I don't know how that would have fixed your misfire issue, though. I've used Motorcraft filters and Mobil 1 oil through several Ford trucks and it works for me.

 

I'm not sure how it would either, but I'm about to swap out oil filters to put a Motorcraft one on there - I'm not sure what brand the shop I went to put on there last week. I'll be mighty happy if it does resolve the misfire issue, though.

 

changing the oil filter to cure a misfire. You have a better chance of getting hit by lightning..