EGR errors

I just wanted to get some input.

I have a '95 3.4L firebird with about 145k miles. The engine seems to be great, but I keep getting errors 75, 76, and 77 which I believe are for the three solenoids on the EGR valve. While trying to get the car to pass emissions, we have put on at least three new EGR valves. It now has a GM EGR valve, but the engine light is still coming on. Just after putting the GM valve on, only one of the trouble codes came back (75, i think). We have also had the EGR ports cleaned, the throttle body cleaned, and the O2 sensors changed.

My question is this: Is it possible for the wiring plug that connects to the EGR valve to cause all of this trouble? To me it makes sense that if it isn't telling the valve to function (b/c of a short or a bad connection or something), then the result would be the same as a bad EGR valve. I'm completely new at this, so don't bash me to badly if my logic is way off!

Any suggestions for the source of the problem?

with what you have already done its very possible that you have a wireing problem

Is it possible to have those codes removed from the computer??
I am not up on the earlier ECU's.

The codes have been cleared several times (every time we hope that we've fixed it!!), but they keep coming back.

Not cleared....removed.

on my 94 I had a problem with that i found out it had a burnt vaccum line right next to but somewhat behind the egr valve that was causeing mine to fail once I got that fixedd dident have a problem.