Uncle Snappy

No....... I have Accel's in it as listed in my signature. The coil tests that was ran showed all coils checked good. The truck runs like a scaled dog when you get down on it. No misfire or skipping. Float along or start out it randomly decides to hesitate slightly or bump after your in motion at 45-50mph.


Strange it runs fine for a 100 miles or so after the plug change and once a load is put on the engine like turning on the ac or heater (without the ac on) the bump, hesitation and increased idle at a stop in drive started again.


Crummy Ford 5.4L engine from the start I'm coming to the conclusion about it.


150,000 miles on it and it should be called a "Yugo scrap it" headache engine instead.


RRRRRRrrrrrrrrrrrr.................

lewissa81

Just a thought, but one or more of the new plugs could have a hairline crack in the porcelain. I know it's doubtful since you have the same symptoms before and after the plug change, but it's possible.

Uncle Snappy

Very well could be. At this point I can't rule out anything related. Very strange brew issue I've never had with any vehicle in 40 years of owning vehicles from various mfg.'s.


Always something.


Thanks for any ideas or solutions so far fellas.

powerranger262

I chased down a bucking issue with my ranger for a year, before it finally threw a misfire code for a hairline crack in a plug. Auto lite plugs to be exact. Switched them back to Motorcrafts, and bingo, misfire gone.

johnny_tucson

don't mean to hijack but I just started to get a big intermittent wiggle when I drop back down to idle. Would a scanner pick up a code for this misfire or might i be chasing for a year like yourself?

powerranger262

Mine wouldn't throw a code until it finally got really bad. Do you have any check engine lights? Have you cleaned MAF, Tb, and fuel filter?

johnny_tucson

no CEL. yes I did the filters, TB and MAF. The plugs only have 4k on them too. I was hoping I could stop by O'rielly, scan and fix the misfire with a quick plug or cop change.

Allinkdupp

Wrong brand spark plugs? That's what mine was

betty_white

Your catalytic convertors could be gunked up, number one reason it happens is from bad plugs not burning off all the gas in those cylinders so the remaining gas shoots through the cats which are made to reduce it but overtime will clog them. When you mostly notice a clogged cat is in between 40-50 mph when at low rpm's. Just throwing that out there, have seen it quite a bit in these f150's. This feeling can go on for several months but one week will just get so bad that you cant even take off without the whole truck stuttering.

bwFX42006

I'm having this same issue, occurs most often when I have the cruise control set at 55 MPH and I encounter a slight incline in grade. As soon as the truck starts slowing down going up the hill, SKIP,SKIP,SKIP,SKIP......then I get mad and stomp the gas and it downshifts and stops skipping. I have 85,000ish miles and haven't touched the plugs or coil packs yet...I'm assuming the skipping is related to that but I'm interested to see what other diagnosis people may have for this issue if it reoccurs after plug and COP replacements.