This is more on egr. L-98, I use a vacuum hand pump directly to the egr valve and pump up full vacuum and it holds fine. I even made a small tool to feel under the plenum at the egr and I could feel that the diaphram was up in the egr as it should be. As soon as I bump the starter the vacuum disappears. I tried to pump up the vacuum with the car running, nothing. I put vacuum on the back of the SR directly to the egr, nothing. With the car running I took the tool I made and pushed up on the egr diaphram and it stumbled like it should. Any ideas.

 

Get a non EGR intake and be done with it...

 

If you want to able to drive your car legally in the Chicago area, that's not a realistic option.

Kwik88, I'd look into the vacuum control solenoid then, maybe it went arye? Had one go bad on before dosen't throw code neither, at least in my case.

 

Wow, that is damned odd. I'm going to keep an eye on this thread. I'd like to see how this turns out, myself.

I do have a question- when you have the engine running and apply vacuum does the EGR valve hold vacuum but just not open?? Or does it somehow mysteriously not even hold vacuum?

If it's the former (holds vacuum but doesn't open) I'd say the valve itself is physically damaged. The pintle is exposed to intake vacuum on one side and exhaust pressure/heat on the other. Perhaps when it returns to it's seat in a running engine it physically wedges itself in there somehow.

 

There are only certan times the egr should function but I don't remember what they are. I am sure you can dig them up with a search. Emgine temp, WOT, decelerate, idling ect.

What is leading you to believe you have an EGR problem befrore you went after it with a vac pump?

 

Light throttle light loads. Basically cruising.

 

There are 2 EGR's - one negative pressure and one positive - could the wrong one cause this? (Just taking a stab here - I really don't know)