Sulfury yellow deposits on a couple of plugs

[Albino 94LTD]

Hey mechanical genius' out there, I changed my plugs last night and found a small amount of sulfury yellow deposit on the two center cylinders. The Bosch platinum4's have been in the truck for about 4 years/60,000 miles.

What would that indicate? if anything.

The color has faded a litttle since last night and the deposits aren't very thick.

It's an OHV 4.0 with 124,000 on the clock.

Thanks
P

 

[Billy177]

this indicates high speed glazing.

lemme guess you like high rpms. no problem just change your plugs

 

[Albino 94LTD]

Can you give me a little more detail?

I don't really stomp on it that much, although going up the last part of I-90 to Snoqualmie Pass @ 70 does put me down in 3rd at about 3200rpm.

I guess it is really not bad for 60,000?

 

[Billy177]

http://www.gnttype.org/techarea/engine/plugs.html

 

[Foo]

Wow, extremely helpful link.

Thanks