UGLY .... REALLY UGLY .... our Silverado currently has just under 90,000 miles on it .... so far, I've been very pleased with its performance .... back at 61,000 miles the dealership cleaned the fuel system and we had to have spark plugs #'s 1, 2, and 4 replaced .... at 87,000 we had to replace spark plug #1 for the second time .... today we had to replace #4 for the second time .... that plug is shown below .... yep, ugly indeed .... we have been told that this generation of spark plug should last 100,000 miles and its not unheard of for them to last 150,000 or more miles .... my local mechanic says he believes the problem is cheap gasoline coupled with the fact that these trucks no longer come with a fuel filter .... any info would be appreciated