Before jumping around to other things, you should get the EGR deal taken care of. Due to chain reactions, looking for other things could mean you're chasing symptoms instead of causes, if you know what I mean. The EGR is a known issue.

 

Jeez man. You have terrible luck.

 

Yes but couldn't the EGR codes be being caused by something else? Because every time I read the codes, it's a different EGR solenoid failing... Or all of them, or two of them but it's never the same codes...

 

Well I fixed the EGR issue. It ended up being the upper intake manifold. I replaced that and it hasn't thrown the code since. But that didn't stop the sputtering and backfiring in the intake and horrid fuel mileage. I took the car to GM today for a diagnosis and It turns out that I have a temp sensor reading -38 degrees, causing the car to run rich. Nice eh? Well I have a new sensor ordered and I'll update when I get it installed!

 

so are you going to cut up the old one so you can see what was wrong? plugged, warped or cracked?

 

I'm thinking about it just to see what the inside looks like. I mean honestly it would have to be pretty bad to be throwing those codes, wouldn't it??