OK, so here are the codes I just pulled using the flashing CEL light method, as I have no code reader:


KOEO: 11 which equals.... System Pass

CM: 33 which equals EGR Valve Opening Not Detected

Next steps?

 

I may have located the problem....

I was inspecting engine again looking for any vacuum lines that were bad or disconnected.

Found one that was disconnected (probably pulled it off accidently when replacing plug wires). It is located on behind distributor. Small part with 2-3 hoses connected to it and some are just caped off at part. Plugged it back in and idle dropped dramatically to a normal rpm. How can I be sure this is what was triggering the Code 33?

Should I clear all codes (by removing jumper wire during system test)?

Thanks

 

Not having a vacuum source hooked to the EGR valve certainly would set a code 33. Yes clear codes and run KOER test. You might not be over hump yet. There should be very little if any vacuum on the hose going from the EVR (see picture below) to the EGR at idle.




Does your EGR look like the one below? Make sure the connector on top is tight and fully seated. The EGR systems in these years can be difficult diagnose. I think Ford implemented a pretty complex software strategy to manage EGR function in the ODBI systems. It worked well but pretty complex.




Was the truck pinging under load?

HTH....Take care.

 

What they said...X2