spark plug question "light brown diposit's"

[Dave84]

ok, i have a missfire at idle, and when uts cold the car only runs on half the cylinders till it warms up, so i decided to pull the plugs and check em, and each and everyone of them had huge amounts of light brown deposits on them, somebody told me its time to do valve guide seals, would that be true?

on the upside i spent the rest of the afternoon detailing the engine compartment
Before:

After

[gadget73]

Looks like crap quality fuels, or lots of uneccesary additives. Light brown is what you want for coloration, but the deposits are usually junk in the fuel that won't burn. If you had oil control problems the plugs would be greasy and oily. You might be running slightly rich, but not too bad.

http://www.4secondsflat.com/plug_chart.html

Might want to try 1 heat range hotter of a plug to see if it helps burn the crap off better, but I wouldn't get worried about valve seals just yet.

[DarkKnight]

Hey Gadget, i hate to tread jack.. But umm, My spark plug color wasent on there.. Mine's fairly white, still just about silver... Whats that one mean? Or well Anyone hehe, not just Gadget

[turbo2256b]

Hey Gadget, i hate to tread jack.. But umm, My spark plug color wasent on there.. Mine's fairly white, still just about silver... Whats that one mean? Or well Anyone hehe, not just Gadget

sort of a flat white is good. Should be a light tan or brown way down in the plug were the metal meets the porcilin had to see down in there. Should be no little black specks on the porcilin.

[nfldfordltd]

When was the last time the plugs were changed? They might just simply be overdue, Ford reccommends changing them every 48,000 kms under light usage such as no extensive idling or driving on gravel roads. I had a bad head gasket on an LTD a couple of years ago and the plugs on the side with the bad head gasket were like that...I used to have to pull them and clean them with a pocket knife every 2-3 weeks. Try a new set of plugs and see what happens. If they get like it again in a short time, then is time to look elsewhere for the problem.

[Dave84]

they where changed just about a year ago

[mrltd]

How much is the car driven? Did't you have a bunch of choke and carb tuning issues? I think they might just need replacing.


My damn car doesn't do anything to the plugs. No deposits at all...

[Dave84]

the car is driven every day

[mrltd]

Distance per year? 15K miles is a general replacement interval...