Will someone please help me
 

I have a 2000 f150 4x4 I change the spark plugs and now in park and neutral it runs fine revs up and all soon as you put it to drive I lose all power when you press the gas and about half power in reverse

Could be the gap in the spark plugs where not set correctly. That's what I'd start with.then is it wires or could packs o. The plugs you may have e gotten the firing order out of place if it has wires

What engine do you have?
What kind of plugs?
What kind of coils?

You probably knocked something loose when doing the plugs, or left something off or misconnected it.