EGR Problem help

[IIv SHaDoW vII]

I posted this on DSMTalk with no responses so maybe someone here can help me determine the problem..

Heres what happened. I took my car to my dads friend who apparently owned a 2g before so he was familiar with the 420a. He looked at my engine and told me the problem was a line from the back of the engine ..(Its one that runs right down by the egr solenoid) wasnt connected to the egr solenoid...so he hooked that up and I started it...drove home (2 minute drive)..and noticed the car was idling like shit. I popped the hood and the egr valve or something from that area was smoking. Im sure it was a part because it didnt smell like wires..so I pulled that hose off of the egr solenoid that he had hooked up and waited... After removing the hose it hasnt smoked since but now whenever I drive it if I switch from park to drive and back to park, it idles wierd..like I can hear it stumbling. Also when decelerating it sounds completely ####ed up like Doop Doop Doop instead of wooooomm. And in a parking lot at Walmart I slowed down and it felt like it wanted to die. So with these symptoms I figured he ####ed my egr valve and now its getting stuck open...but I tried plugging the vacuum hose to it and it still does it. Any ideas...also before I get flamed for letting a douche mess with my car instead of fixing it myself, He is paying for any damage he caused that I need to replace. BTW this is a 98 automatic GS
420a... .So any ideas?
Before he hooked the hose to the egr solenoid, it didnt have any hose on the front of it..I have looked at pictures and I know there should be something going to it so I figured he was right.. but before he messed it up the car ran fine.
I would just buy a block off plate and say #### it.. but emissions is a big deal here where I live..

 

[fourreGsixty3]

There is supose to be a vacuum source from the intake manifold. Im thinking either the EGR is stuck due to build up inside of it from the vacuum source not being hooked up for a while. Not trying to shot gun the problem, but the EGR is at fault here because it is open when it shouldn't be( decel, idle, most likely robbing you of power at WOT), and emission's is a big deal, and the guy is willing to pay for what ever needs to be replaced to get your car running right again so order a new EGR valve. Is it hard to start the car if it is cold(car being cold, not weather)?

 

[IIv SHaDoW vII]

First off...thanks for the reply.
I didnt have any problems starting it when it was about 30 degrees outside.. Ive only had this car for about 4 months and thats the coldest its been. I'll order the EGR tomorrow. When I replace it should I put that hose back on it? Also, the actual hose was the one hooked to the egr solenoid, so with that unhooked is the egr system disabled? Reason Im asking this is because I had no problems whatsoever until that hose was hooked back up.. then all the egr symptoms kicked in. Also, why would the egr valve or whatever from that area smoke when that hose was put back on?.. Thanks again for the help...much appreciated