When I'm cutting across grade in the ditch the tractor starts to die out. The grade is only about 25 degrees and if I turn straight up hill it catches again and runs fine. Since it's a diesel I can't see this being a fuel issue. I am leaned quite a bit to the uphill side for balance so I might be taking some weight off the seat safety switch, but I thought being a switch it would either be on or off, not intermittent. Anyone run into this before 