2000 f150 knocking

I have a 2000 f150 knocking cant figure out what it is I thought maybe it was rod knocking so I pulled the plug wires and it continues to knock sounds like its coming from the bottom of the motor could this be crank shaft problems ? don't know.i dont want to spend money for nothing.
any thoughts would be helpful

This doesn't sound good. A knock from the bottom of the engine is usually a spun bearing or a loose connecting rod. Either way, the engine will have to come out and it will have be at least partially torn down to pinpoint the problem. Low end knocks like this can result in the death of an engine to the point where it can't even be rebuilt, so I suggest that you don't run it until you figure out what's wrong and fix it.

My son borrowed my Honda Accord for awhile. An exhaust mount ahead of the muffler tore out and made the exhaust so loud he didn't hear the engine knock. The nuts on a push rod had come loose and finally came off. The piston rod then punched a whole in the side of the block and completely ruined the whole engine. If he had let me know about the exhaust leak so I could fix it, or fixed it himself, then the knock might have been heard early and the engine shutdown to do a full investigation before the total loss. I've always guessed he did something he shouldn't have to rip out that exhaust hanger is why he didn't tell me.

I have a 2000 f150 knocking cant figure out what it is I thought maybe it was rod knocking so I pulled the plug wires and it continues to knock sounds like its coming from the bottom of the motor could this be crank shaft problems ? don't know.i dont want to spend money for nothing.
any thoughts would be helpful

Use a manual pressure gauge and check oil pressure as a bad bearing usually causes low oil pressure. If around 10psi at idle. Put the vehicle on 4 jack stands if you have clearance to remove the pan you can clean the strainer. Pull the bearing caps if the crank looks good you can purchase slightly oversize bearings at an automotive machine shop.