Can anyone help me figure out why these codes keep showing up. I recently bought a 1989 S5 NA from the mazda dealership and had to have them change the AFM and then these codes showed up. I know what the codes are, I just need help to fix them.

 

Your metering oil pump is bad, car probably drives like crap. Do not continue driving, if you are lucky, the OMP has not fried the ECU. You will need a new OMP. Code 13 is due to a bad pressure sensor itself or rubber line going to the intake manifold or worst case, the wires running to the pressure sensor.

 

thats the thing though the check engine light goes away if you shut the car off and start it back up and then it takes 20 to 30 min to come back on. I checked the line for the pressure sensor and it is brand new.

 

Keep driving the car like this, you will have more problems than you can ask for. If you don't believe me, use the search button and see how many people have had their ECUs fried.

 

next question is what are the differences between an s4 NA pressure sensor and an S5 NA sensor and will it work for the S5 cause I have an S4 NA rx7 that doesn't run.

 

Screw that my S4 has giving me enough problems

 

You can't interchange any pressure sensors. The voltage scales are totally different. You have an S5 NA, so you need one for an S5 NA (N35x).

Check wiring/connections to the sensor and your MOP/OMP, then replace both if needed. You should probably also open the ECU and check for fried circuits.