First: On my 86 420sel i have a stripped lugbolt on the passenger rear wheel. Can I just tap new threads in there or do I need to replace something?

Second: Does everyone's 420sel start up nice and easy in the morning? It seems mine takes two cranks to get it going and then it stumbles for a couple of seconds before it idles. Also it doesent have high idle like all of my other cars(non-merc).