Well, the descriptions of this 'feature' suck - but I cannot do any better.
I just hooked up my 219-days-without-piston-slap/door-crack truck with 10K on the clock to my trailer for some camping with the family beginning tomorrow.
Well, in trying out the trailer for the first time on this truck, of course I put my foot in it's throat just-because.
Well, as it was gaining momentum at around the 3,500-4,500 range I heard a raspiness (had to change at least a word from the descriptions just to keep you thinking) that I didn't think should be there -- and immediately got out of the throttle.
I'm hoping that it is valve noise coming through the plastic intake manifold -- and that it's really normal.
I haven't sprung for a set of real Ford manuals yet -- but think I heard someone talking about some valve that opens somewhere in the intake manifold to open the left-bank into the right bank (or perhaps it was that nice Manhattan the little woman brought me).
You know that it is a curse of mechanics to always hear the worst in their engines -- while the blissfully-ignorant never seem to have problems.
Toreador Red, Keyless XLT SC SB 5.4L E4x4 4wDisc/ABS, 3.73LS, Skid, HD 7700# Towing, LT-245's on Chrome, Tube-Steps, Captain's, 6CD, Tonneau, named: "Nick"