You read all the bulletins so good luck. Had my plugs changed at slightly over 100,000. He did the heating up engine and let it cool and reheat to certain temp. Broke them loose a little and squirted break free or some solvent in around the plugs. Let it work for a while and backed them out.
One thing I did was run fuel system cleaner through the tank before taking it in. It was supposed to clean carbon etc too.
He showed me a couple of plugs. The threads looked pretty clean with some blackening but no build up. I think one was still broken.
The electrodes were pretty well worn. Get a better spark with wider gap but it strains the coils etc. Had to replace number 8 coil.
