Spark plugs going short circuit - normal?

My RRC is a 3.5EFI running on petrol. It tends to run rich, which is a problem I am having trouble getting to the bottom of. But this is background info.

My specific question is about the spark plugs. On starting from cold I usually get one cylinder which tends to missfire until the engine has warmed up a bit. I know I need new dizzy cap and leads (genuine), because the root cause is possibly a weak spark. In the meantime when I remove the offending plug it is sooty and sometimes wet. Several times when I have removed it I have found that the plug is short circuited between the central electrode and the body. Cleaning it with carb cleaner sorted it yesterday, but the same has happened again today. It starts perfectly from cold with a clean plug.

The plugs are the correct NGK and only a few hundred miles old, (say 6 months as I only use the Rangie for trips to the tip and pay & play days).

I have also checked the old plugs which I removed a few months ago, and the are shorted too.

Is it normal for a sooty plug to be short-circuited?

Pete

Wet sooty plugs can break down, used to happen often on the racing strokers. Try fitting a hotter running plug. Used to warm the strokers up on hot running plugs (soft plugs) and then swap to the racing plugs.