my audi i currently being a bitch, after having a fuel injector come randomly unplugged the other day i have had drivability problems and low oil pressure, after the turbo spools i get a stumble and when it's warm and i'm at an idle my low oil pressure light comes on. i hooked up a mechanical oil pressure gauge and it says that i have 10psi at warm idle, it's a 1.8T with 156k miles on it. I really don't know where to start. the only thing i can think of is i recently changed my oil and i put in 10w40 oil.