Misfire on highway,Spark plugs today

[Hotrod Lincoln]

The other day we were headed back from Vail at about 75mph and felt a shudder, or vibration. My CEL was flashing slowly, then 10 seconds later, it was gone. Running fine.

I ordered some SP534's and installed them today. Pretty easy install. Didn't have to unhook anything but I did crack the corner of a COP but just put it back on. All in took about 1-1.25 hours. Everything was very clean. The old ones were gapped 40-42 and one was at 45-46. New ones were set at 31.

Seems to run good. Hopefully that took care of the issue.  The old ones were 528's. they didn't look horrible but definitely tired.

 

[Macgyver]

Ouch. Thats a big gap.

Hopefully that is the cause.

If it was winter. I would say some bad gas too.

 

[Hotrod Lincoln]

Ouch. Thats a big gap.

Hopefully that is the cause.

If it was winter. I would say some bad gas too.

Yeah, I hope it's fixed. I only use 91 Costco gas. I was worried that I might have put 85 octane in it by accident but told the wife I don't think I would have overlooked that.

 

[ZSHO]

The platinum MC SP-528 look original based on the rust buildup on the porcelain. Z
I would of ordered some new COP for some reassurance.

NGK 58978
6 COP Boots Req'd; No Wires Req'd (Only 19 Remaining)
$3.71 ea

http://www.rockauto.com/en/catalog/lincoln,2011,mks,3.5l+v6+turbocharged,1446518,ignition,spark+plug+/+coil-on-plug+boot,10150

 

[SHOdded]

Good riddance to the 528s.  They are prone to having issues anyway, as noted in Ford's TSB.  Agreed on a new COP anyway, keep the old one as a backup/tester.

I guess no trouble getting the boots off?  Plenty of stories about boots "welding" themselves to the plugs.  PITA from experience

 

[Hotrod Lincoln]

Good riddance to the 528s.  They are prone to having issues anyway, as noted in Ford's TSB.  Agreed on a new COP anyway, keep the old one as a backup/tester.

I guess no trouble getting the boots off?  Plenty of stories about boots "welding" themselves to the plugs.  PITA from experience

No. They looked perfect. The only one I had problems with was the one. It wasn't the boots either. It was just sealed really well. I already ordered a new COP per Z and you.

 

[SHOdded]

Rock it then sir!  :thumb:

 

[Macgyver]

Running Good now?

 

[Hotrod Lincoln]

Running Good now?

Seems like it has better throttle response and I have yet to have it misfire again, although I haven't driven it more than a 15 minute highway ride yet. It does seem to have noticeable more power than it did. As wide as the gaps were it sure seems to me that was the problem.