I just purchased a 1999 Civic lx 5spd from a Sheriff's seizure auction. 105k miles not sure if timing belt has been changed...probably not. The vehicle sat for 18mos on the impound lot till I fired it up and drove it home. The check engine light came on an once the engine had warmed up the idle surges from about 1000 rpm to 2000 rpm...low, high...low high...I took it to Autozone and the code says:
1) loose fuel cap.
2) Vapor canister saturated.
3) Failed vent solenoid
4) Failed purge solenoid.

I am confused because the codes are P0505 & P1457. Can anyone shed any light on these issues or make any suggestions?