what a pain in the neck

 

i think something else is going on with the motor. unless the engine has been used in extreme conditions or been subjected to some really nasty or the wrong octane fuel, you shouldn't have carboned up plugs to the point that the motor will not run.

it's possible that the car has been used in unusually dusty conditions and the air filter was overloaded. it's also possible that the fuel being used is too high an octane. the higher octane fuels have extra chemicals/additives in them to meet the higher octane/anti-knock requirments and if used in an engine that doesn't call for the higher octane, then deposits can form in the c/c, valves, plugs, etc. this is something that is rather common...it's not an off the wall occurence.

also, it could be the brand of fuel; some auto makers call for "top tier" fuel only...one brand is shell, there are others listed if you google top tier. the top tier fuels have higher amounts of detergent chemicals to keep the engine fuel system clean.

one last point and i don't mean to be a gloom and doomer, but: does the engine use alot of oil between changes? like a quart or more in less than 600/800 miles? if so, then the problem may be more with the internals, such as the rings or the valves/valve seats. if it does have high oil consumption, it could also be related back to the brand/octane of the fuel used. excessive deposits in the combustion chamber can lead to higher oil usage.

i hope i'm wrong, but i would definitely not use premium and i would find a top tier brand in your area. also keep any eye on the oil consumption.


jackg
06 sts6