Why is it the ERG valve keeps frying in my Bravada?

What is your question?

I own one of these monsters (the Bravada) and I can not keep the EGR valve functioning.I replaced one 5 months ago and it's out again.It runs rough and idles poorly,blackens oil really fast,and burns gas really rich. I recently replaced the spark plugs and wires.It seemed to run a little more smoothly.Then two weeks later it died on the side of the road needing the starter replaced.I replaced the starter and found that I had to replace the black battery cable as well.Now it runs worse than before, burns all kinds of gas and the only code that comes up when tested is the ERG valve.I am replacing it again.But what the heck is going on here? Is there anyway to prevent this again?