How would i know if my EGR valve on my 302 ford engine is working properly or not???

if you have a vacuum pump disconnect the vacuum line and pull a vacuum on the valve while the car is idleing when you pull a vacuum the car should studder and stall

is there anything else that can be done to check it???

you can start the car and manually push up the diaphram but that is only 50/50 because the diaphram might be leaking. or yo can bite the bullet and remove it and see if it is clogged.
why do you think its bad anyway?

because the check engine light comes on while driving or when you rev the motor... but the diaphram doesn't appear to be moving...

the check engine light coming on while driving could be a number of things.
what kind of car is it? what year?

Poor mans check:
Put a piece of vac hose on the valve and suck on it. Put one finger in the underside of the valve and feel for one of the openings that goes to the diaphram and feel to see if it moves when you apply vacuum. If its working, you will feel it move and the engine will miss badly or die.

Its also possible that the EGR passage that is in the intake is plugged or that the end of the EGR valve is carboned up. It could still appear to move, but be plugged.

1989 ford mustang with a 302, the reason for suspecting the ERG is because i had a buddy that had his valve or vaccum hose or something changed and the light went out... and i was told to check the ERG valve or vaccum hose...

that or it's and o2 sensor

like jmark said do you have any vacuum hose laying around?

yea, i'll give it a try and see what it does for me... other than the valve what can i check?? for the light?

there should be a memory code i would go to an autozone and get them to read your codes.

the car has been brought in but they weren't sure so i didn't want to start changing parts... and rack up a huge bill...

did they run codes?

they said they did but didn't find anything... im starting to think they were just too lazy to do it...

you could go buy a cheap codereader from a parts store i dont think they cost anymore than 40$