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Check engine light will come on if the intake gaskets are messed up. Should be a P0171 and P0174 IIRC. A leaky gasket there will cause a lean condition due to the vacuum leak from the bad seal. Just went through that on my V6 F150. I've never really heard of the S197's having intake gasket problems.
....as stated, he has a V6 so everything you just stated doesnt apply....
If it's a V6, then I stand corrected regarding most of my comments on the spark plugs and wires. However, the 100K replacement schedule which I mentioned for the spark plugs still applies.