F-150

Pretty much got the lock problem figured out, but it ain't fixed yet. My problem now is that my truck hesitates sometimes (becoming more frequent) and it's starting to worry me. The other day I was getting on the highway and I hit the gas to accelerate and the RMPs didn't go anywhere. The truck didn't quit, and the RMPs didn't really go down, but the truck didn't accelerate. Could it be the throttle position sensor? My old Dodge had a problem with them (changed it twice in less than a year) that would cause the truck not to idle, and run funny sometimes. I also thought it could be the spark plugs. I haven't checked them yet, but I will today. If they look like sh*t I'll change them. Thanks guys.

I forgot to add that the engine is a 4.6L V8. And while I'm at it, how do you change the spark plugs in this thing? I'm not too familiar with Ford trucks, at least not these newer ones.