Colorado80201

I have a 2000 F150 with a 5.4 Triton. It knocks (more like a hammer sound emanating from inside engine) only at 2500-2600 RPMs. The only DTC code it has tripped is P0300 and this was climbing up a steep highway. Any ideas?

Welder7018

Any knock is a bad knock. It can possibly be a loose connecting rod vibrating only at those rpms. It could also be detonating.

Jacob.P93

X2 does it sound like a Ping?

Welder7018

If it sounds like a hammer the engine is pretty much trash. BUT if its a pinging type knock its fixable. But involves full rebuild.

4x4dave

Check your spark-plugs for signs of detonation. I'd change them anyways if your getting a misfiring code. Check compression and use higher octane until you figure out what is causing this misfire.

Colorado80201

Thank you everybody for your replies. Here is some more info:
1. It's a sharp noise that comes from top of engine, as opposed to a thudding noise from inside of engine.
2. The noise doesn't happen on really cold or really hot days.
3. Octane booster reduces noise.
4. It never happens at any other RPMs.
Any more ideas?

4x4dave

If octane booster reduces noise you have found the problem.

Detonation or pre-ignition is occurring inside your cylinder. Your cylinder is firing at the wrong point in the combustion cycle. See youtube vid for more explanation.

You HAVE to run premium fuel untill you get this fixed (higher octane is less susceptible to pre-ignition and detonation). As mentioned before get this fixed asap or you will ruin your engine. You need to pull and inspect your sparkplugs and likely replace them all. Incorrect gap, incorrect heatrange, incorrect plugs, old plugs, carbon buildup, bad gas, vacuum leaks can all contribute to pre-ignition. Extra heat inside your cylinders is your worst enemy. Check your cooling system too.

I hope your cylinder and head is not already fubr'd