EGR QUESTIONS???

I am also having big problems with my egr stuff. if u want to PM me i will tell you what i have already done but i was having some similar problems to u. I took the EGR valve off and cleaned it out to remove all the carbon from the little pintle and seal. Then i checked the function of the diaphram to see if it worked correctly. But i put it all back together and the car is still running like crap. I havent pulled codes yet to see if its still there because i have some other problems i need to deal with also. But i think it is my EGR sensor (the plastic connection on the end of the valve) ...so i ordered on of those. I dont know how much vac those lines are supposed to pull, but either way it should pull vac untill wot when it would shut off and let all the exhaust flow out. good luck man

Here’s an EGR test procedure I copied from cjones

to check the EGR valve:
bring the engine to normal temp.
connect a vacuum pump to the EGR Valve
apply 5 in vacuum to the valve.
if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
snap throttle to 2500 RPMs (remember snap the throttle don't hold it there).
did the vacuum gauge show about 5 in vacuum?

if not, check for manifold vacuum at the EGR vacuum valve.
if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPMs.
should read about 5 in vacuum

See http://www.veryuseful.com/mustang/tech/engine/images/88Stang5.0Vacuum.gif for vacuum line information.