1990 GMC C1500 Check engine light

The CEL coming On the computer has identifed a problem within the engine management system. You need to pull the code/s. Below is how you do it and comeback with the code/s

If I did it right there was three codes:

32
43
12

Diagnostic Trouble Codes - 1990
Chevrolet
13 Open Oxygen Sensor Circuit
14 Coolant Temperature Sensor (High Temp Indicated)
15 Coolant Temperature Sensor (Low Temp Indicated)
21 Throttle Position Sensor (Signal Voltage High)
22 Throttle Position Sensor (Signal Voltage Low)
23 Manifold Air Temperature (MAT) Low Temp Indicated
24 Vehicle Speed Sensor (VSS) Circuit
25 Manifold Air Temperature (MAT) High Temp Indicated
32 Exhaust Gas Recirculation (EGR) Circuit
33 Manifold Absolute Pressure Sensor Circuit (High Sig.)
34 Manifold Absolute Pressure Sensor Circuit (Low Sig.)
42 Electronic Spark Timing (EST) Circuit
43 Electronic Spark Control (ESC) Circuit
44 Oxygen Sensor Circuit (Lean Exhaust Indicated)
45 Oxygen Sensor Circuit (Rich Exhaust Indicated)
51 Faulty PROM
52 Fuel CALPAK Error or Missing
54 Fuel Pump Circuit (Low Voltage)
55 55 ECM Error

Thanks young man this give me something to work with.......
Lloyd

Wow! you make me feel so good as a senior citizen Thank you Sir

I to am a senior citizen and we are young men !!!!!