mattwright101

ok
so ive been having this sort of missing problem for the past week or so
i checked my plugs today and all of them looked brand new except for one
it looks sort of a light brownish color on the ceramic part of it
anyone have any idea what that means?
its not a dark brown at all just a slight brownish tone to it

67mustang302

It means it has the proper a/f ratio. The others are leaner, which is fine.

mattwright101

so the problem isnt the one plug its all the others?
great

mattwright101

another thing i noticed while under the hood today is that i think my harmonic balancer has slipped
it is showing that im running at around 30 degrees. i know that im nowhere near there of course because i get no pinging or detonation and the car runs pretty decent where its at
should i replace the balancer?

67mustang302

No, not really. All white/clean is fine as long as the plug doesn't show signs of running excessively lean/hot. Most EFI setups run on the lean side for emissions/mileage. You'll actually make better power in some setups running on the leaner side of acceptable if detonation and heat can be controlled. Chances are you have an injector slightly out of balance or a flow imbalance in the intake etc. Unless you get into high dollar race tuning, chances are all of your cylinders won't run the same, but they'll be close.

On my carb'd setup for instance, it's tuned so the plugs are slightly light greyish-brown and it runs good and gets decent mileage. Going up just 1 jet size increases the fuel by ~2% and is enough to cause the plugs to be the "ideal" brown, but all it does is decrease my mileage.

It depends on the setup though, higher compression, or boosted cars tend to make better power on the richer side of the ideal range, since that's where detonation can be controlled.