A gas smell on the plugs could be from a very immediate recent condition, like I drove 1.5 miles to the grocery store and back in 40 degree weather. The car never warmed up, sure it's running rich. for that trip only, not necessarily in general. I read that a good way to judge plugs for mixture at WOT is to drag race the car and turn it off just past the end of the 1/4 mile strip, careful you may lose some brake vacuum, then pull the plugs.