[elhigh]

Whew!

Regardless of whether they've caused your Check Engine light to come on, you may want to pull your grille blocks before taking your truck in for warranty work. Some service writers can be real sphincters about vehicle mods vis-a-vis warranty violations.

I think you're right about the vertical grille openings, though - they're probably safe to block off. And what little bit of your tow hooks is projecting through your existing blocks shouldn't be an issue.

Hey, I've got a funky fuel gauge too - at fill-ups, the gauge goes to the top, but it drops to E over about the next 75 miles. 325 miles later, the warning light comes on.