Rmbb

I recently bought a 91 Corsica with the 3.1 V6 engine. It's not running very well. Fault codes 43 and 45. I'm thinking maybe the knock sensor. I understand it's located behind the engine, seems difficult to get to. I want to disconnect or disable the knock sensor somehow so to see if there will be any change in how the car runs. If it starts to run more stable then maybe it really is the knock sensor that needs replacement.

The car has 55 000 miles and is otherwise in excellent condition. Bought it from a 79-year old man who bought it new in 1991. Today he's stuck with a oxygen tube so he felt he couldn't use the car anymore.

PS The Power steering feels really heavy. It was low on oil, I filled it up to the mark but there's no change. PS pump bad?