Callling All Calif. Camaro Owners! Smog Problem EGR carbonation cost?

Hi, I have a '93 V-6 Camaro 3.4l

On a dyno when doing a STAR smog test on my 141k mi. '93 Camaro, the motor revved up real high and the rpm's went high, thereafter

I was told by the Tech that my car was misfiring....did I know that?

I said no, it was running super smooth

He informed me that the NOx (Nitrous oxide) was too high and caused the car to fail Calif. smog, he said also that the cause of the misfire were burnt spark plug wires.

After I got in the car and drove it, immediately I was like "hey, what's wrong with the car, it runs rough,"

It was misfiring like the Tech at the smog shop said

I told myself maybe the High rpm dyno smog test caused the spark plug wires to burn off?

Anyway, I changed ALL 6 spark plugs and the car ran smoothly,

When I faxed the Star Smog report to my Regular, Trusty Auto Repair Shop Mechanic *WHO BY THE WAY, HIS SMOG TEST MACHINE IS TEMPORARILY BROKEN*, he said, hey you just barely FAILED smog, maybe it was the burnt spark plug wires that caused the High NOX levels?

He said my make and model and year has an EGR system

and it might be carbonated

I will have him (my Trusty Regular Mechanic Repair shop) do another smog test, after i file a PNO (planned non operation ) with the DMV, early next week because my registration expires on 2/2/18 --very very soon --

he said he will have to study the car to see if:

"there is Carbonation"? on the EGR system?

That probably means that the EGR system or the EGR valve is dirty with carbonation?

I'm not sure.

Here are my 4 questions:
1) Normally how much does this cost to fix the EGR system so it passes Calif. smog?

2) How many hours of work?

3) Are the parts expensive??

4) Is it a simple enough small job for a DIY?

5) Who here thinks that it was in all likelihood the spark plug burnt wires and the resulting misfire that caused my car to fail smog?

My trusty Regular mechanic shop dude told me that the EGR system if cleaned or fixed has a lot to do with lowering Emissions and if that is done, there is a greater chance of passing smog


Thanks in advance for your help, member-friends