EGR Problems

Ok the car is a 1987 Bonny. 3.8l Car started running very rough at idle. I unplugged the EGR valve and it smoothed out. Plug it back in same thing, rough. I replaced the EGR Sensor and still the same thing. It's not the valve obviously, you can see it work when you plug it in, it goes to full open and chokes the car with exhaust. I know the computer has to be telling it to open for some odd reason. What tell the computer to open EGR when at cruising speed?
Also, sometimes it will run fine till I shut it off, then it wont restart till it cools off. I checked fuel pump pressure, right at specs. Any ideas?

Anyone???? Anyone at all?

It could be the valve. possible bad return spring.
Most egr's are vacuum controlled, are you sure you diddn't disconect the idle control valve? I did that once and could not for the life of me figure out what my mistake was for several hours, very confusing.

More info.Are you sure it is EGR, any codes set?

Did you clean the port out when you replaced the EGR valve?
If you didnt, its probly plugged.

The egr is electric, GM has been using them for years, and it would be doing it all the time if the port was cloggged. Like I said it goes to full "choke" when I plug it in, you can see the valve open to all the way. Returnes to normal when I unplug it. And yes its the EGR valve because I just replaced it yesturday just to see if maybe the coil in it was shorted out. Still, same problem......

What about maf or IAC sensors.Any codes , how old are plugs and wires.

Only code that comes up is EGR. Plugs and wires are not even a year old. It has had new coils, ign module within the last two years.

How about leaks in the hose or gasket.

3.8's are known to have pluged stove pipes and cracked intakes where the EGR mounts.

If those check could be an ECM issue or wiring.

That did cross my mind, but that is only true to the newer 3.8 with the plastic intakes. That just happened two weeks ago to my dads Buick, the plastic intake cracked allowing coolant to enter the intake. I dropped in a new intake and egr stove pipe.
But this is different, some reason the computer is telling the Egr to the full open position. soon as I unplug it closes "obviously" and engine purrs like a kitten. I need to find out what signals the computer to make it want to go to full open... I checked the fuses, put new egr on and new egr sensor. The computer has to see the right conditions to allow this to happen like, steady load on engine, operating temp. I just don't want to keep throwing parts at it.
Does anyone by chance know the OHM value of the coolant temp sensor at a cold condition?

GOT IT! I traced down the wires leading back to the computer. Found the wire that the computer grounds broken and was grounding itself. I repaired the wire and presto Its fixed. Thanks to the people that tried helping me out. I apperciate your ideas!

What wire exactly was it NIC

Blue wire, it had gotton worn through and going to dead ground