Pricing for Exhaust system oxygen sensors

i have a honda accord ex 1991 and when im parked waiting for the lights to change my car is idleing fast and putt putt there is a sound of air inside the hood can you please answer my question?

Sounds like you have a vacuum hose disconnected and with a vacuum leak you will have a high idle and hear air while its running, But make sure the engine is off before trying to find the hose or leak