After a bunch of money thrown at this, I finally got a resolution. After replacing all the coil plugs and spark plugs, the problem persisted. After talking with my mechanic, he talked about transmission shudder. Getting a transmission service is what fixed the shudder. I’d had my transmission serviced at 100k miles, but at 160k miles it needed it done again. The transmission fluid was a dark brown, instead of the normal red. They replaced 7 quarts. There is another 7 quarts in the torque converter that they couldn’t change. I’m taking it back for another draining of the 7 quarts in the pan and replacing that. Should bring the color back to close to normal.
Chasing a problem, but there being two issues makes it difficult to fix.

If you haven’t had your transmission service in 30 or 40k miles, get it done, hopefully that’ll get rid of your problem.

 

Exact same problem. Was assuming / hoping plugs. Just changed them this weekend. None looked too bad. Haven't had a chance to floor it yet to see if it happens again.

It = Engine light comes on, shuddering until I let off the gas, eventually goes away and engine light goes off. No codes stored. Has happened twice in about a year, both time when flooring it on the interstate to try to stay alive. Spoiler alert....still alive.

 

Yeah, my check engine light blinked, but there were no error codes on my odbc reader. Before, when I would accelerate onto the freeway and thr turbos kick in, it would buck, as soon as I let off, it stopped.

 

I had cylinder misfires on my 2015 3.5 EB. Mine were caused by a bad O2 sensor. There are O2 sensors on both sides of the exhaust manifold. My misfires were coming on the same side. Got the 02 sensor replaced by the dealer (after they argued with me about it). No problems since

For several ultimately minor issues, I found them for the dealer using my "FORSCAN lite" app on my phone. It reads EVERYTHING. Highly recommend. Saved my *** when I had a intermittent throttle body fault. Nothing like going into "limp mode" in the Wyoming wilderness with a travel trailer. Had to clear it 3-4 times to get home. But I got home instead of being stranded 100 miles from civilization. The dealer told me I needed a software update to fix it. I said BS. I got 1 mile from the dealer before it went back into "limp mode." Reset it again, drove back, and told them to replace the damn throttle body (under warranty). They did that but broke a wire to the AC compressor in the process - and then tried to tell me it was broke when I brought it in. I told them BS again. After troubleshooting, they fixed it "out of courtesy" even though they broke it and it was still under warranty.

 

Sometimes you can get a misfire because the spark plug gap is too wide. The symptoms can be basically what's been frequently described in this thread. Engine starts/runs good but bucks when you do relatively heavy acceleration. This is often described as "spark plug blowout." I've had this happen with my previous car and I've had it happen with my current pickup. The spark plug gap from the factory was MUCH wider than it should have been. The gap should have been pretty narrow and I should have caught that just by looking at the plugs... but I was a bit tired and didn't catch it. Once I regapped the plugs, the problem completely went away. If you're seeing this symptom, check your plugs and coil packs first. If it happens right after your plugs were changed, check the spark plug gap. The poster above also suggests thinking a bit deeper about the problem. If the problem is all on one side, I doubt the problem is with the plugs and coil packs. Bad O2 sensors can cause the truck to run too rich or too lean on one side.

I do have to say, though, I'm not a mechanic by any stretch of the imagination and this is my first vehicle with 2 O2 sensor banks... but bad O2 sensors can cause drivability problems. As can a cylinder with low compression.

 

Just want to throw this out there as it might help someone but i had a 2015 3.5 eco and would get the shudders and go into limp mode when flooring it. I changed all the spark plugs and coil packs, it didn't help. Changed the turbos, it didn't help. It ended up being my exhaust manifolds were warped. The codes said boost leak btw.

 

This is an older post, but I wanted to post this as I was experiencing the same issue. I read about replacing the boots, but didn’t quite get how a rubber boot could be a problem just being a weekend mechanic.

I was experiencing pretty hard jerking when I got around 3,000 rpms, 60 mph, pulling a trailer. Put in OEM spark plugs – SP594, replaced the top MAP sensor with an OEM as it was pretty dirty, cleaned the others.

Got a little better, but it was still jerking with an apparent misfire, no CEL, even when not pulling the trailer.

So I started pulling the coil and boots and I pulled the first boot off and then saw the coil spring inside and understood better why people said to replace the boots. But looking at the coil spring inside, I saw a white substance on the end of the coil spring that attaches to the spark plug. It is the same white substance/corrosion that you see on a battery that has not been changed for some time. So I started carefully pulling the coil springs out of the boot, briefly sand papered the upper end that makes contact in the coil pack, and then cleaning off the end that attaches to the spark plug. I did this on all six and found one that was much worse than the others. That had to be the one with the misfire. I also checked the contact point in the coil pack to make sure there was no corrosion there.

I cleaned the inside of the boot, spread a thin layer of dielectric grease in the spark plug end and put the coil spring back in the boot and pushed it back on the coil pack.

I took the truck out and went up a couple of steep hills and punched it up to 3,000 rpm with absolutely no hiccup, jerk or hesitation. It was firing on all cylinders and cruised up the hills no problem.

It was a white substance that had accumulated on the coil spring, but it completely cleans off leaving no degradation to the coil spring, at least in my case. 2018 Ford F150 2.7L Lariat with 115,000 miles.

Hope this can helps others.