P0470 and PO340 Codes 1997 Aspire - EGR and CAM sensor?

I have these codes on a 97 Aspire for my daughter's 1st car. Its been running her around fine for almost a year now and we've gone to a lot of trouble to get it in good interior and running shape. I looked these codes up and it says it is "Exhaust Pressure Sensor Malfunction" and "Camshaft Position Sensor Circuit Malfunction". I would normally assume this means I may need to clean, adjust or replace these sensors or their wiring, but what is scary is that I've looked in the normal places online and I cannot find either of these parts mentioned anywhere. Anyone got any clues here?