[PRUNEDA]

My '89 Chevy truck has a 350TBI. I checked for trouble codes and it gave me 32,34,45. I researched and found the what the codes represent. Which one should I check/replace first? I'm not sure if a bad EGR valvle will trigger a bad MAP Sensor as well. A couple of months ago I installed Edelbrock headers and replaced the O2 sensor while I was at it. Later on I read that it is preferably to install a heated O2 sensor due to the exhaust cooling. Just need suggestions on what/how to check for a faulty sensor. Thanks in advance.

CODE 32-EGR system=
Faulty EGR valve.

Faulty or loose wiring and/or connections at the EGR solenoid.

Faulty, loose and/or leaking vacuum hoses to EGR valve

CODE 34-Manifold Absolute Pressure (MAP) sensor=
Faulty or loose wiring and/or connections at the ECM.

Faulty MAP sensor

CODE 45-Rich Exhaust
Faulty oxygen sensor