Car going off on up,,sounds like either valve block is needing looked at, or dodgy contactor,,,can't be governor as only work on down,,and can't be rupture valve either as same,,then again,,,if guys have been working on it, and it goes off again, I would be asking serious questions as to why the can't find out what's going on,,and keep pushing them,,indeed, tell them to get their technician in,,as long as they pay for it!