2016 cylinder misfire issue

[beanford]

Hey, looking for some advice on my 2016 ford expedition 3.5L 135k miles.

Had CEL first started under heavy load (60mph, diving uphill, etc) pulled codes and got misfire cylinder 6 and a few random misfire codes. So I replaced the plugs and now I’m only getting a cylinder 3 misfire.

I replace the cylinder 3 coil Make sure the coil was seated on 3 and still getting a misfire without CEL and a P303 code.

So I took it to a local chain shop for a diagnostic. They said it was probably a fuel injector. They however were not confident in that fact so I decided to take it to a Ford dealer.

They old me I replaced the wrong coil, I don’t think I did based on the attached picture for cylinder location, but they said they swapped it to confirm and that it is not a coil issue but that it has a bad fuel injector.

They replaced the bad fuel injector (I asked them to replace all 3 since they had the manifold off and their tech only replaced the one which was frustrating)

Tonight we are driving up a canyon and start feeling misfiring again. Not CEL and it has been 3 days since we picked it up and have not had a misfire until tonight.

I don’t trust the dealer at this point anyone else have any suggestions where I should look next to solve this?

 

[JasonH]

Check the plug gap. You can swap coils to see if the issue follows a specific coil. Cylinder 3 is passenger side closest to the firewall.

 

[beanford]

Check the plug gap. You can swap coils to see if the issue follows a specific coil. Cylinder 3 is passenger side closest to the firewall.

I swapped coils, the shop swapped coils and the dealer swapped coils. It stayed on cylinder 3 each time.

Also I have not checked the plug gap but 6 new plugs were installed that come pre gapped from what I understand.

 

[tacoduck]

Ugh. Subbed for outcome.

 

[gimmesomecoffee]

.

 

[drbr0b0tnik]

What brand of plug? Cause motorcraft are garbage (and their pregap is as garbage as they are). I replaced mine with NGK Ruthenium gapped at .028 and I've not experienced a single misfire since.

Edit: I forgot that I also ordered mine one step colder.

 

[JasonH]

I swapped coils, the shop swapped coils and the dealer swapped coils. It stayed on cylinder 3 each time.

Also I have not checked the plug gap but 6 new plugs were installed that come pre gapped from what I understand.

Check the plug gap and check the insulator for damage. Easiest thing is to swap the plugs between cylinders after checking and see if the issue follows the plug. Sounds like this was done for the coil but not the plug itself.

 

[beanford]

What brand of plug? Cause motorcraft are garbage (and their pregap is as garbage as they are). I replaced mine with NGK Ruthenium gapped at .028 and I've not experienced a single misfire since.

Edit: I forgot that I also ordered mine one step colder.

I replaced them with NKG but I did not check the gap since they were supposed to be pre gapped. I will check the gap and see where they come in.

 

[beanford]

Check the plug gap and check the insulator for damage. Easiest thing is to swap the plugs between cylinders after checking and see if the issue follows the plug. Sounds like this was done for the coil but not the plug itself.

You are correct I swapped the coils but not the plugs.

 

[beanford]

Well an interesting development. I know the Expedition was misfiring on Saturday driving up the canyon took it to the auto parts store today and had them pull codes and there was not a code to pull. Not sure what to make of that.

 

[MidnightBruce]

Good afternoon! Man, it sounds like you've had a really difficult time chasing this down.

I will share my story a little bit of my vehicle and hopefully it might spark an idea of why your vehicle is exhibiting some of the symptoms it is.

I have a 2016 EL 3.5L And even though we don't tow very often,when we do I've never had an issue. 105,000, mi on the ticker and the only things I've ever done to this vehicle are a water pump replacement at 50k and a CV joint that had a leaking boot in the rear at the same time. At about 60,000 mi We were experiencing bucking while under load And after doing some research I drilled the 1/64-in hole on the driver side bottom of the intercooler at the lowest point. It definitely weeps out a ton of blow-by. So I have to stuff paper towel at that location to absorb most of the moisture and keep it from dripping. That being said, this thing has never once given me an issue as I did have some of the bucking problems before. I also regularly use full synthetic 5W40 And use the Lucas Oil full system fuel cleaner every 6,000 mi. As well as use the turbo direct injection cleaner every 3K. Most of these things are just preventative, but I believe they have helped with preventing some of these issues. I replaced my spark plugs And spark plug boots every 30k and I gap them at 0.027 And I checked the gap every 10K. I often drive the vehicle very spirited with lots of wot full pulls through all the gears when I am behind the wheel. Since this is my wife's car, it doesn't get driven very spirited unless I'm in the driver's seat.

I really hope you do get some resolution to this as chasing down a random misfire that doesn't show up in the codes is very very challenging.

 

[JasonH]

I really hope you do get some resolution to this as chasing down a random misfire that doesn't show up in the codes is very very challenging.

I sent my wife halfway across the country to visit some newfound discovered relatives and the engine was misfiring at heavy load. She has a lead foot. Found one of those blue shop towels in the filter box when she got back. Ooops...my bad.

 

[BlackBetty]

I found that pulling your sensors and cleaning them helped me when I got misfires. Out of the three I pulled the MAP sensor was the nastiest; would be saturated in dirty oil. Of course I would see improvement after cleaning… right up until it would get nasty all over again. Adding a catch can help me resolve this issue.

 

[GlennSullivan]

I swapped coils, the shop swapped coils and the dealer swapped coils. It stayed on cylinder 3 each time.

Also I have not checked the plug gap but 6 new plugs were installed that come pre gapped from what I understand.

I've read all that crap about pre-gapped spark plugs and every time i swap plugs on any of our vehicles, I ALWAYS find a few gapped wrong - by a lot.

 

[drbr0b0tnik]

I've read all that crap about pre-gapped spark plugs and every time i swap plugs on any of our vehicles, I ALWAYS find a few gapped wrong - by a lot.

This. I remember reading on here a while back when I was going through my plug woes, a guy who had to go back to his retailer like 3 times before he got plugs that were all pre-gapped in spec.

 

[5pencer]

Did you ever find a resolution? I’m hunting a similar misfire issue.