I have a 2000 f150 4.2l v6 stick shift. I have just replaced a drivers side exhaust manifold after doing so the motor had a very loud ping/ring sound. It is possible that the spoons has been there I just bought it a week ago. Not only doe it sound funky but it runs like crap.. Is stutters a bit in first,second, and fifth. I also have no power the truck can not reach over 65. I put a new o2 censor, spark plugs, with no change. I had it hooked up to a computer and a pressure test done. Which came up with nothing. I have no clue what to do. Anything can help thanks

 

Possibly you reversed the spark plug wires for cylinders 5 and 6.

On my '99, the coil pack does NOT match the configuration of the motor on #5 and #6. IOTW, the wire that looks like it goes to cylinder 5 actually goes to 6.

 

I agree with Dave.But,I have also seen broke plugs and a bad coil do the same thing.

 

One other thing causes this too; installing aftermarket spark plugs other then Motorcraft. Been there,done that.