I've got sheepskin covers & usually get zapped big time when I close the door. But if I'm standing on grass when closing the door, I don't get zapped. If I'm wearing leather work boots, I don't get zapped on either grass, concrete or tar, if I'm wearing cheap shoes with rubber soles, I get zapped on concrete or tar but not on grass! Go figure!!
It's a pain getting zapped by my truck, crikeys, I always hear the zap & sometimes I can actually see the spark!!! Er, maybe I'm "Electric" after all!
Maybe the strap from chassis to ground is the go!
Cheers
Doinit