Deerhunter4

FYI. I have driven several thousand miles since regapping mine and I'm confident that the truck runs better. Smooth idle and no shuddering.

focus289

I would agree with you. The truck idles much better. Never had the shudder issue. Hope to never have it.

TwinTurboFx4

X2

gwpfan

I took mine in due to rough idle, was out of town last week and one morning was likely around 50 deg F. Startup it shook and I thought the truck was going to die. I noticed too the RPM gauge bouncing, it may have been some before but I don't think that much as the whole truck just didn't seem as smooth. Runs just a bit rough even at a stop light. Then I thought maybe poor gas, but after second tank and still seeing the rpm gauge bounce like it did I took it in, oil change was close to due anyway and figured I have a warranty, let them look at it.
I asked them if they had or new of any issues with spark plug gap differences and they said no knowledge. As to the issue I get a report of:
"No info for concern on oasis, eec test - no DTC's present, pass cont/koeo/koer self tests, let vehicle sit for 4 hours..overnight and performed power balance test at cold start- no problem found, all PID's within normal ranges, some tachometer fluctuation at idle is normal on this vehicle and is a normal operating characteristic due to the sensitivity of the gauge."
Who knows, maybe my plugs will all be within normal range, but I will check soon myself and if I do find they are out I will definitely let them know and update here.

boosted150

Umm... I think the techs are missing the point. The truck may not throw a code, but I definitely know what you're talking about. It is a mis-fire, or at least it feels like one. Is the tech sitting in the truck when they are evaluating it? You can feel the loss of engine balance when it happens. Mine does the exact same thing, but only when cold. The tach may be sensitive, but that's not the answer to the problem.

I gapped my stock plugs, but they were all already at 0.034-0.035 so that didn't help the issue. I'm going to try new NGK's in a couple of days when I get some time off.

Joewee3.5

I pulled plugs and all were between .038-.040. I replaced them with the NGK IX gapped to .030. I can't really tell anything at idle. At full throttle it pulls smoother. It used to have a strange rubberband feel around 5k and that's gone.

clubsfit

Hey guys, I went back to my parts dept, pulled 6 new plugs off the shelf. They ranged from .035-.041 brand new.... I have had the same miss/stutter usually around the 4000-4500 RPM mark. I run a 93 octane race tune, and it is not all the time, but seems to getting more noticeable. So, I decided to gap them all to .030, and install them, and measure the gaps on my factory plugs and see the difference.

clubsfit

Just like I figured. They were all way different, ranged from .032 to .044!!! I will report back after driving with them all set at .030.

f150man3.5

Checked and regaped mine today. They ranged from .35-.44. Runs real smooth now

HogFan

X3