Again, fuel filter. If you haven't replaced it in the last year, or ever, I would almost bet money that this is at least a partial cause of your
problem. It can clog up in six months or less if you drive a lot.
Sounds like your brother might have unplug a sensor or broke a wire,put a scan tool on it,after you make a visual to check if anything was
unhooked,oil would have no bearing on motor,unless you ran out of it