Prizm using way to much oil

I have a 1998 Chevy Prizm/ Geo Prizm. It goes through about a quart of oil every thousand miles. The oil isn't leaking but i believe it is being burned becasue there is stuff on the inside of my exhaust pipe. A friend told me it could be my piston rod, or rings. Does anyone know what it could be. It also knocks when i accelerate, when i push on the gas it has a hard time accelerating. Please help I know nothing about cars...

Critical points: It knocks on accel, has a hard time accelerating.

these are symptoms of oil being burned. Check your plugs, they are probably oil fouled. The most common cause is valve seals, then worn piston rings. Goto the store and buy some "anti-foul adapters" they work pretty well. Install new plugs when you put them in. When you are replacing them, do a compression test both wet and dry. Post the results. If you don't know how, then post that and I'll reply in a day or so with instructions.