check engine light came on , checked with code reader, catalyst effeciency below threshold, below bank 1, car runs fine, mpg 24-25 city, did a search front o2 sensor , headers, etc... any opions, ??? also my wife may not have put gas cap on tight enough ,

Start here: http://www.motor.com/magazine/pdfs/102006_09.pdf

Clear the code and see if it comes back. If it does, check or replace the front O2 sensor with a Subaru Part.

 

Many times that will fix it.

 

I take it you have done normal maintenance, NGK Plugs, Subaru Plug Wires....

 

Good Luck.

for future reference...Gas cap being let loose/off will not throw this code...Chances are it would set an EVAP leak code...

i have not changed the plugs or wires since i bought it, 38,000mi ago, ok on the gas cap losse code, yes i cleared the code , i do have a subaru o2 sensor [ new] sitting in abox , thanks,