'94 K1500 Suburban 350/4L60E (110,000 miles)
What would cause deposits on the spark plugs in this engine on only 3
cylinders? Cyl. #2, #4, #8 all had deposits on the plugs. #2 and #4 had
LOTS of junk on them, where as #8 just had a little. New plugs, wires, cap,
rotor at 90,000 miles.
All the others looked perfectly normal- nice clean burning. No green tint
to the deposits (as it may be with Anti-freeze on them). Compression was
good, 145-160 psi. Deposits looked to be whitish tan in color and covered
the end of the plug more than half way around.
I don't run fuel additives or anything of the sort (dry gas occasionally in
the winter months).
Any hints on this one?