How do you do a plug chopmif it breaks up and won’t clear out in any gear. Sound like I have a stutter box stuck at like 7000 rpm

Drive down the road, hold it wide open for a bit and kill the motor while doing so.  Pull the clutch in and coast to a stop.  Check the plug. 

I believe there is a sticky post about plug chops i copied from the interwebs.

does it just break up when wide open?  or will it do it at other throttle positions?