1997 Honda Accord Errors

1997 Honda Accord 4-cyl VTEC engine light is on. Autozone diagnostic tester displayed these possible errors/causes:
P0401 – EGR insufficient flow, possible EGR Valve, blocked EGR passages in engine;

P0171 – (1) Fuel system too lean bank 1 (Cly #1), large vacuum leak [I found a disconnected hose between valve cover (Cyl#1) and air intake], (2) Fuel system concern, (3) Ignition system concern, (4) MAF sensor faulty, (5) HO2S/AF ratio sensor fault.

P0453 – (1) Sensor circuit high voltage, (2) Open or short circuit condtion, (3) Poor electrical condition, (4) Faulty FTP sensor.

I don’t know where these sensors are located and whether I should change them out if other possible causes might produce the same errors. I found a hose disconnected between the valve cover at #1 Cyl and the air intake.

Can someone shed some light on what might be wrong and how I should proceed?

Julian

I looked for vacuum leaks and found a hose disconnected at the #1 Cyl valve cover. The other end was connected to the air intake cover. If I knew where the sensors in question are, I might be able to check the wiring and do some continuity and voltage checks.