I used an OBD reader from Innova, the 3120b that does OBD1 and OBD2, and got two codes:

032 - Exhaust gas recirculation (EGR) valve diagnostic switch - closed during engine start-up or open when EGR flow requested by ECM; manifold absolute pressure (MAP) sensor - signal voltage is low.

042 - Electronic spark timing (EST) circuit - open or shorted.

I checked the following link and matched the codes to what was listed: https://www.thirdgen.org/service-eng...ht-error-codes

Any ideas what I need to do to fix these problems?

 

There are fault finding charts in the factory service manuals to work through.
The code only shows a fault with the system ; not that the item itself is actually faulty.
The computer say for example; expects to see a certain voltage under certain conditions.If the wire was broken or grounded then that would not happens so a code is thrown

 

Ok, so I should check for faults in the circuitry before looking at the parts themselves?