I've got a 97 Z28 which has not been in my good graces lately because for the past 3 months my service engine soon light has been lit. The error code says I have an EGR flow problem. My gas cap is on tight, I've put in a new O2 sensor and EGR solenoid. If anyone can help I'd appreciate it.

 

Might try cleaning the EGR valve or replacing it.
You have more than one O2 sensor as well.