when looking at my spark plugs while the engine is running..one of them i can see a spark jumping from the metal heat shield over it to the plug...drives great..no SES light...what is this and should i do something about it?

 

Arc due to spark energy leakage. If it is coming from the boot, try some dielectric grease on it. If it is jumping off of the wire, it probably has some slight damage that is letting the spark leak out.

 

it looks like its sparking off the actual plug to the metal boot sheild

 

If it is not creeping out from under the boot, then maybe you have a funky plug.

 

when the engines cold should i just unscrew it and screw it back in? thanks shoebox