djfllmn

iTrader: (1)

usually all it takes is 1 coil going bad to cause a shudder under light acceleration. Seen that plenty of times

fx4_seafan

Makes sense to a degree. Usually it shudders when trying to keep a constant speed between 45-60mph. I normally just power through it lol

Jbrew

And that's how you know it's a coil. Shudder/miss right after the shift into OD (at about 45mph)...coils (cop) failure under that specific load is popular. Research that and you'll come to same conclusion. This is called a low grade misfire failure and it's due to shorted turns in the coils internal windings. Shorted turns add up with time eventually compromising integrity.

You can get away with just replacing the one that went bad. However, if all the coils are from the same litter, your best bet is to replace the set. Once one fails, most likely the rest will fail in domino fashion...this is common.

When replacing coils, the replacements have to be properly thermal protected with dual build magnets. Otherwise they will fail again in the near future. Spec coils are branded Motorcraft or Denso. Those are the ONLY 2 choices you have if you want to steer clear of repeated coil failures....and pulling your hair out lol.

fx4_seafan

Okay, I was just going to ask if I should just run the cheaper coils that are on RockAuto.. Autozone wants 30$ a coil for Denso, I don't daily drive this, so I'm not in a huge rush to order the Denso vs. the cheaper option on RockAuto.....

djfllmn

iTrader: (1)

how often do you want to do the job?

fx4_seafan

For the extra 20$ for all 8 Denso I'll just go that route. Glad I hopped on here before ordering!

fx4_seafan

Update for everyone. Was running the truck around town tonight and CEL came back on, this time from cylinder 3 as another misfire. Unknown at this point if coil was switched from cylinder 2 to 3 at spark plug change 200 miles ago... I switched coil pack on cylinder 3 to cylinder 2 and will wait to see what happens.

Jbrew

Yea the mechanic most likley switched #2 with 3 when he did the plugs. The last time I updated coils, I found a Motorcraft set on a ebay site that were cheaper than Denso from RockA. I fried my old set while welding in silicon bronze grounding lugs..whoops lol. Lost the PCM as well. Anyway, sometimes Motorcraft can be had cheaper, most of the time Densos will be cheaper. Same coils.

fx4_seafan

I ended up ordering a set off Amazon. Couldn't wait a week and a half on a new set. And I wasn't about to spend 250$ at Autozone for a set. I drive this truck MAYBE 2000/yr. It's mainly used for pulling the boat out of the water and hauling the snowmobiles in the winter. Not a daily driver. The misfire just pisses me off. Lol.

fx4_seafan

And in regards to switching the coils around, yes he did confirm that he did. So I have a coil going up. But with the truck having 211K miles and knowing what the plugs looked like coming out, I'm just gonna get them all swapped out and start fresh.