gas and air flow meter
No, it will not.
Lean Condition caused by bad or restricted injectors
p300 is a misfire
You need a OBD 2 scanner/reader to erase the codes
Yes you need all OBD codes clear to pass testing
You need an OBD scanner or take it to your local Auto Parts store. Stores like Advance auto parts can usually read codes for you. The generic codes they read out can be converted to Volvo's OBD codes. The generic codes usually start with the letter P.
Once erased, the codes are gone.
OBD codes that start with a P are power train codes.
obd (1) codes are generic, same for all domestic obd(1) two or three digit codes
If you want the OBD codes, try this site: http://autorepair.about.com/library/ts/obd-i/bl-dtcs-63a.htm?once=true&
Need to know if you have OBD I or OBD II or tell us what year the Chevrolet is.