So I just bought a 2003 Chevy 2500hd crew cab 4wd. It has 160k on it and was bought with one sensor (knock sensor) making the check engine light go off. Now there are two other sensors (oxygen switch and oil pressure sensor) going off.

Can these sensors be connected to one problem? Are they easily fixed? I love the truck an I want to fix it, but if it's going to be something huge, I don't know if it'll be with it.

Any ideas/help/advice?

Thanks!