If you have a vac gauge and infrared temp gun the egr is a 10 min test. Pump up the egr to see if it holds vac. If pass, hook the vac gauge up to the output of the switchover valve. When warmed up rev the engine (should be able to move the throttle behind the aircleaner, but I have a m103 so not sure) and the gauge should jump with the revs. Also the temp of the egr tube should change when measured by the temp gun if not clogged.