cleaning the spark plugs? I noticed a lot of filmy black stuff on my spark plugs. I cleaned them gapped them and reinstalled them. Should I use an engine flush to clean out the apparent sludge in my car? This car had a blown headgasket and I replaced everything down to the alternator and timing belt. Is there probably some residual oil in the block? I changed the oil and filter. It runs but I bet it could start a little easier, what do you think?

i had 1 which dd the same a gas additive helped alot