I have a 07 F150 that I recently changed the spark plugs on (what a pain!). Anyway, I noticed the gas smell inside my cab after the change. I went back and made sure the plugs were torqued to 25 ft/lbs, and that made it much better. There is still a slight gas smell when I run the heat/air from outside air, but it's drastically reduced and it's mostly just when I first crank the engine. Does anybody have any recommendations for totally eliminating it? Should I torque the plugs to 28 or 30 ft/lbs?

 

Did you use high temperature nickel antiseize on the plug barrels?

 

The sleeve or threads?

 

The antisieze goes on the long sleeve, none needed on the threads. If on the threads, it can cause a torque misread.

 

I did put a slight amount on the threads. Does that mean I may need to torque them a little more?

 

Pull them out, clean all the antiseize off, then reapply it to the sleeves.

 

I did put anit-sieze on the sleeves and a slight amount on the threads. Sorry for the dumb question, but how can this slight amount on the threads cause the plug to not seal completely?

 

It can't. At ~25lbs yer CLEAN (and I stress CLEAN) tapered plug seat mating surface is a Gas-Tght seal. ANY spooge between those machined surfaces can defeat this seal.

The tiny amount on the thread ( it IS a tiny amount, right?) is not an issue as long as you took it into account during retorquing. I myself always apply a miniscule amount. Old-school. And I've never had a sparkplug related issue.

More info here on derating values: http://www.densoiridium.com/installationguide.php

Did you remove / disturb the fuel rail during yer R&R work? Worth checking, perhaps - them o-rings can be pesky.

Good luck
MGD