i bought the 4.6 liter V-8 and mine taps while accelerating. it also hesitates when i smash the gas to pass. it sounds like a valve tap to me. it also does this when at idle.

i have just over 2,000 miles on it and it still taps.

it's annoying. i'm not so sure this is a mark of craftmanship.

in my opinion it shouldn't tap brand new...period!

 

It may be detonation (spark knock)!! Try premium gas, if that stops it, get it checked out soon! RW

 

My 04 5.4 makes a "tapping" sound at idle. I don't notice it at any other speed. And I can only hear it with the radio and heater fan off, and listening for it intently. I don't believe it is in the valve train. I believe it is in some ancillary component, such as a power steering pump, or some other device. I've heard others mention this, so I believe it is a common sound in these engine bays.

Matter of fact, it bears mentioning that, even if this *is* coming from the valve train, it isn't necessarily anything to be concerned about. I've also got an 01 Mazda Miata, and it can really set up a rapping sound from the valves, especially on cold starts. On the earlier engines, closer to 1990, they are notorious for valve tapping, at all times, but especially after being run hard and hot. Even so, these are among the most hardy engines in any small car. They routinely last 200k miles, just tapping all the way.

 

um, i would get it checked out first. owners manual specifically says NOT to put premium gas in the truck.

 

It does, however, say that Ford doesn't approve the use of 86 octane available as regular in higher elevation regions (such as where I live). Because of this, I use the middle grade, 88 octane, in mine, because there is no 87 octane available up here.