89 with three engine codes.

Code 13 = oxygen sensor
Code 32 = EGR system
Code 33 = map sensor.
I do not have a FSM, all I have is the hanes book (better than nothing).

On the oxygen sensor, I was going to just replace it and see if that fixes the problem unless there is a way to test the circuit and see if something else is causing the problem. Any tech info on this will be greatly appreciated. I was also wondering if the oxygen sensor would make the other two codes show up, if not does anyone know what I can do to test these as well so I can determine the fix for the problem.

Thank you in advance for your time and your knowledge.
Swap the O2 sensor, change out the 2 MAF sensor relays on the firewall behind the battery. Visualy check the electrical connections/wiring for the EGR protion of the smog system.
Clear the store trouble codes (disconnect the battery for a minute or so) start the car and see what codes/issues still need to be addressed.






