I had LOF, air and fuel filter replaced when I bought my 06.
Engine idled smoothly, but seemed a little sluggish.
Its a 3.0 L with 70,000 km (43,000 miles).
On a hunch I had the complete injection system including MAF & IAC cleaned and then the plugs replaced.
Ford Motorcraft plugs.
Engine seems like a different beast if you can call a 3.0 a beast.
Revs up much quicker and pulls smoother.
Definately worth the money to do this preventative maintenance.
I'm gonna check my mileage now to compare.