I recall early years of the 3100 were notorious for the passage between the intake and EGR clogging. I have not seen that as much on the modern LA1 3400, but clearly still happens. Considering you mentioned the EGR has a wiring harness spliced in that has all white wires, I would try and get a junk yard harness, fix it back to a factory harness, matching colors properly and get an EGR for this engine that uses the factory plug. Avoid chasing down problems from using aftermarket parts that are not a direct replacement. And to be honest, I would not hesitate using a junk yard EGR as long as they don't charge much for it. I honestly don't recall ever hearing one fail on a 3400 (I am sure they do, but my guess is that it is pretty rare).

 

Was good till lastnite now has a verytough shaky idle but runs gine when driving. Just at idle and stop lights etc.. it was runninv oerfect then just crapped. Ang help?

 

The way you describe that sounds like a faulty sensor or solenoid somewhere. If you are still having EGR problems, this can be part of those issues. Are you still throwing codes for any issues?

 

still the same closed position code was getting . Found a wiring diagram lastnite and looked and its wired up correctly as long as A,B,C,D go in that order on piogtail from left to right. Problem is my wires are faded i believe. I have Red,Brown< (no black wire, grey with black stripe(x2) and a yellow and whit stripe and yellow black stripe???

 

I did some looking myself. This is the exact wiring for the EGR in a 2000 Monte with a 3400. And if your pigtail connector is NOT this connector, I strongly suggest you abandon this, get a OEM type and the correct connector (even if it involves going to the junk yard to get the parts). This is one of the reasons I HATE replacement parts that want you to cut the factory connector and splice in their connector. Fuel pump assemblies are notorious for that. I will skip and go with an OEM style connector any time.

But this can be related to that performance problem because the EGR is not functioning as it should.