it's not pinging
it's not piston slap
it's not valvetrain
it MIGHT be motor mounts
it makes a hard to describe noise only if you push the pedal past halfway (like to accelerate to merge with traffic)
when cruising or putting around town, quiet as a mouse.
Has anyone had engine or exhaust system to body contact that made a noise during acceleration? Anything typical I should look for? Has anyone had issues that were cured by replacing motor mounts? and what is that baby shock absorber that you can see in the driver's side front wheel well??

 

the little shock is ford's attempt and muffling some of the motor's rattling. V6's aren't very harmonically balanced, couple that with it always wanted to twist off the motor mounts and wahhlaahh, small shock is supposed to fix all that.....rolls eyes lol

I think my truck does the same thing...it sounds and runs more rough above a certain RPM value, and I never could figure out what it was. so I just left it....

How much louder does your's get?

 

Check the inside of the radiator shroud where the fan sits inside.See if the fan has been rubbing toward the top half. Sometimes the fan blades at the ends will show wear. If an engine mount is broken,the engine will twist from the broke side under acceleration. The fan moves with the engine but the shroud is stationary , so the fan hits the shroud.

 

as far as how much louder, it is probably (decibel wise) less than double, but now I focus on it and it pi$$e$ me off. I rarely use more than half throttle because of it, and while that helps my gas mileage some, sometime you need to whip it to merge with traffic.
I have checked on the cost of motor mounts and they aren't cheap. I suppose if that little shock was shot, it would increase the harshness, but all the time? or only when accelerating hard?

and thanks, I'll check my shroud/fan tonight!

rechecked motor mount cost at Rock Auto, not as bad as I thought, cheap in fact.