A co-worker of mine has a 1994 k3500 chev,4x4 454v8 at,ps,pb,ac,with duel fuel tanks.It works fine on one tank but when he switches to the other tank it blows the fuse,but if he switches it at idle it will run untill you put in gear then it blows the fuse again.It will idle and rev up with no problems on this one tank till you put it in gear.