95 Aurora stalling

[kkiley]

95 w/ 180,000 miles. I have owned the car for about 8 months and have had the following done: fuel rail recall in Dec, which started a missing out issue. Replace the MAP sensor, did not fix issue. It started stalling out when warmed up, and I have replaced the throttle position, idle control sensor and recently the computer.
the car runs perfect until warmed up, then if you are moving above idle up to about 40 miles an hour and remove your foot from the gas pedal, the pedal will come all the way up and the car will die. If you keep your foot on the gas, holding the rpm's to about 500, you can feel the idle sensor take over and it idles perfectly.
It acts like it's a vaccum leak. I have a gasket covering the EGR valve, and it has no effect on the performance or stalling.
With the new computer, the engine runs perfectly, except for the stalling. Any suggestions as how to diagnois the idle falling off?

[tjm]

do you have any codes from the check engine light?
How does it start?
Have you checked the fuel pressure regulator? (very common)
check all vacuum lines especially the PCV Valve elbows (known to dry rot) and lines.
replace PCV valve.
re-torque the intake manifold and check the backfire flap with some throttle body spray.

[kkiley]

Originally Posted by tjm

do you have any codes from the check engine light?
How does it start?
Have you checked the fuel pressure regulator? (very common)
check all vacuum lines especially the PCV Valve elbows (known to dry rot) and lines.
replace PCV valve.
re-torque the intake manifold and check the backfire flap with some throttle body spray.

Since it is a 95, I have not taken back to the dealer to run codes. The vehicle starts fine, the FPR was just replaced in Dec when update was done. PCV elbows are fine, tightened intake manifold and cleaned throttle opening.
Vehicle runs just fine until warmed up, but still dies if moving less than 10 mph and remove your foot from accelerator (after warmed up).
Where is the backfire valve? I am going to replace the PCV valve tonight and see if that helps.
It is so close to running good all the time, just seems like there's a vacuum issue when warmed up.
Thanks for your thoughts.

[apollo7879]

Point of information: The FPV is not replaced when the fuel rail mod is performed.

[tjm]

The backfire flap is on the intake - almost underneath on the passenger side. Just spray some carb cleaner in that area and see if your idle changes as you spray - its a good way to check for vac leaks

However, your issue is sounding more like the EGR valve. when the car is hot does it idle rough or just not at all (dies)? - You may have a sticky EGR valve (stuck open) - The EGR should not be open at idle but they are known to get sticky with carbon deposites. pick up a new gasket and remove the EGR valve and clean it and the associated ports with carb cleaner.
http://www.howardm.net/dred98/egr.php