kaci1989

my problem was detonation or spark knock! i first put premium gas in after a few days of driving i noticed some improvements but it still made the noise once in a while. then i went to my local parts store and purchased a can of cumbustion cleaner and sprayed it in through the throttle body while running. after that it pretty much never happens, only time it happens is when it is really hot out and pulling a load. (i heard sea foam works really well) my truck had alot of carbon built up in the cumbustion chamber and it was causing the spark knock.
i would recomend using a higher octane gas, it will keep things cleaner internally.

kaboom10

I personally use Amsoil fuel system cleaner and conditioner or zMax fuel system cleaner and oil additive. For sludge I use AutoRx every 25,000 miles. Engine runs like it got a load of ExLax in the gas tank.

brian92288

my 05 f150 with the 4.6 has been making the noise for the longest time... after searching everything for the noise, i finally got around to pulling the cats apart. a piece of the honeycomb inside broke apart and rattles at a certian engine vibration and flow through the cats.

Ryan150

It's completely normal for the engine to make that noise under load or going up a hill. Your engine is just pinging. When you dig the pedal into the floor it will ping, as well as when you are going up a decent sized hill, because your making the motor really work.

michael chap

I have a F150 with 160k on it with a 4.6 L engine. I pull a camper and boat with mine (not at same time!) on a fairly routine basis and each weighs about 5K. About two years ago I started getting the pinging sound when the truck was going about 40-60 mph and accelerating. It was especially bad when I was pulling a load. I removed the egr valve and cleaned it even though it didn't look very dirty. I also removed the metal pipe that runs from the exhaust up to the egr valve. It has two smaller pipes that branch off from it that are hooked up to rubber vacuum tubes. Don't know what they run to. There apparently is a screen or something about half way down the tube as you cannot run anything all the way down the tube. I used brake fluid cleaner and shot it down the tube and into the smaller side tubes. I then blew compressed air through the tubes. Hooked it back up and, viola, pinging problem went completley away! Just recently the pinging returned and I removed just the tube and cleaned it. Most of the problem went away again. Probably need to remove the egr valve also and clean it to completely solve the problem.

JulieOffRoad

I've had that light ticking/rattle sound under load and at high RPMs for years. Truck is a 4.6 '98 and I remember hearing it in '03 and about 100k miles ago. Hopefully yours isn't anything more serious.. or can be explained by the fixes in this thread.

My engine makes horribly loud noise now though, and I dont know if it's related. The noise now is a heavier ticking, but not a deep knock. It's louder under load and in drive than it is when revved in neutral or park.. though it's loud in park on startup if it's cold. The tick speed varies with the RPM but seems loudest around 1200rpms.. like when lightly accelerating from a stop. An engine guy says it's likely piston slap and there's nothing I can do to fix it. The noise is much louder than it was a week or two ago and I feel like I'm driving a time bomb. Hope yours doesnt progress to this! Any thoughts or ideas would be greatly appreciated!

Thanks,
Julie

papa tiger

Put some premium gas in it and run it on the interstate hard for a hour. Burn the carbon out of it. You may have a faulty spark knock sensor do you show a trouble code if knock come in. A bad cam adjuster can create a noise also. If you have EGR clean/replace it. Also PCV valve can really plug up after 40,000 miles. Replace it.

MaM83

I agree with papa put premium in,i had the same prob untill I started putting in premium, haven't heard the noise since...