1993Z

They are EGR codes I belive but I dont know where to start to find the problem. Sometimes the SES light comes on right away and sometimes it takes a few minutes. Sometimes while driving and sometimes while idleing. Where do I start?

Injuneer

Use Shoebox's code list, for LT1's. Look at the column on the right for the 93 code differences.

http://shbox.com/1/Dtcs.htm

DTC 32 is lack of EGR flow. DTC 26 is the #1 Quad Driver Module that powers the AIR pump, EGR vacuum solenoid and EVAP purge solenoid. Check for a blown fuse for the AIR pump. Check for a faulty solenoid. Or it could be the QDM itself.

Fastbird93

Here are service manual scans from a 93 FSM for those codes:

Code 26:
http://www.fastbird93.com/diagnostics/dtc26p1.jpg
http://www.fastbird93.com/diagnostics/dtc26.jpg

Code 32:
http://www.fastbird93.com/diagnostics/dtc32p1.jpg
http://www.fastbird93.com/diagnostics/dtc32p2.jpg
http://www.fastbird93.com/diagnostics/DTC32%20Page1.jpg
http://www.fastbird93.com/diagnostics/DTC32%20Page2.jpg

All 93 DTC's scanned from the 93 FSM:
http://www.fastbird93.com/Diagnostics.htm