F'n EGR....but its required.

I'm guessing it's a B series truck,this is from Alldata. I hope it helps

• Testing and Inspection

1. Remove air cleaner.
2. Start engine and run it until it reaches normal operating temperature, then shut off engine.
3. Disconnect vacuum hose between EGR valve and water thermo valve at EGR valve.
4. Disconnect vacuum hose between intake manifold and vacuum amplifier at vacuum amplifier.
5. Connect hose disconnected at vacuum amplifier to EGR valve.
6. Pinch hose connected to EGR valve and ensure engine idles smoothly.
7. Release pinch and ensure that engine idles rough or stalls.
8. Connect all hoses to proper locations.
9. If test results are unsatisfactory, clean or replace EGR valve as necessary