I had some truck problems (shaking and pinging) I didnt know what the deal was, so I took out my chip, it still kept hesitating and shaking, I didnt know what was going on so I had my friend Mark (autothrottle) look at it and he thought it might be a bad spark plug, but we agreed it was only running 7 cylinders, I took it to Ford to see what they said and the guy from ford called me today and they said a spark plug was totally gone, they replaced it and the truck's compression ratio was off, they couldnt figure out why and called me back when they figured out that the valve was blown, so now they are sending a ford tech to look at my truck on friday and they wont give me a car to drive or anything because they said I have too many mods on my car (exhaust, chip, air kit). What do you guys think of this? I dont think those mods cause this kind of failure in an engine, I think it was the factory's fault for not replacing my spark plugs when they replaced my supercharger. So whats your input?