I think you should show the mechanic your "cleaned" EGR valve and ask him how he cleaned it, maybe try to get some of your money back and you should vist the Better Buisness Bureau.
On a 95 camaro confusing it for OBD II is easy to do, people on this board are still confused, so that is understanable. And lastly I have to say that there are crooks in all professions and it suck you have to be carefull, but there are a lot honest mechanics out there and even honest people make mistakes. (BTW I once had a mechanic tell me my intake manifold gasket was probably leaking coolant because i was loosing coolant fast and couldn't find a leak. Obviously this was not the problem since coolant does not flow through the intake manifold, but only someone familiar with the LT1 engine would know that. Later, with my trusted mechanic it took us several hours to find the problem, my radiator cap)

 

I do all the work on my car but I got a recall for the air pump and so I went to the local GM to get it done .
I have a K+N cold air system on it so I asked if it would be a problem and the said they would have to charge me extra .
So I went home and put the old one back in and then took the car for the recall .
When I got the car back I looked to see the new parts they put in and the whole air cleaner assemble was loose and no clamps were put back on and not even the hose was connected to the MAP so unfiltered air was going in to the motor .
I went back and showed them and all they said was they would take the car back in and finish it . Never said sorry or nothing so I took the car and finished it myself .
My point is if I didn't know any thing about cars the engine would of sucked dirty air till the next oil change and would have they caught it then ?

 

Don't even get me started! Shops have enough trouble with stock cars, don't even think about taking in a modified one.

Back when I was a relative lazy newbie with clean soft hands, I paid a local dealer to replace my plug wires. I supplied the wires, and they "charged me extra" due to the supercharger (which is understandable)...so, $300 IN LABOR later I drove off happy that some other poor sap had done the job. Shortly after my supercharger bearing went out and we discovered that there was only 1 bolt left holding it and even that one was partially backed out! There's supposed to be 6 or 7 on the bracket....they'd all backed out and disappeared! I remember looking over the job to make sure everything looked right, but I never thought to check if they bolts were tight. So after ANOTHER $400 or so later for the blower rebuild, everything was back to normal.

The second even more painful experience was after I got my car back when the tranny took a dump. GM put a new one in and covered it 50% under warranty, WITH the supercharger installed...sounding pretty good so far, right?

When I picked up the car, one of the shop guys was asking me what "that little **** on the dash is for, it doesn't seem to do anything"...he was referring to the timing retard ****. Then he proceeded to tell me that he doesn't know why I ever put a supercharger on the car, since "first and second gear are completely useless now, all it does is spins the tires". Shortly after that, hello "chug of death"...now, I realize I can never prove they caused it, and I'll never know for sure, but you can damn well bet another dealer won't be touching my car.