2005 5.7 4WD QC, 88,XXX

Those that have been here a while may be familiar with my recurring EGR valve troubles. Factory one went out at about four years, then it's been about a steady two years between. I just threw a code again today, but it's been right at about a year since I changed out the last one. Any ideas on why it keeps crapping out? Another underlying cause that needs fixing? I can fix it when it goes wrong -- that's easy enough, but my knowledge is too limited to diagnose anything further, admittedly.

Thanks in advance.

 

My '03 doesn't have one. My 300C does, though. I took it off and cleaned it a couple of years ago. It hasn't thrown a code since. What kind of gas are you using?

 

Mid-grade, but it does have 10% ethanol here. The first one went south shortly after arrival in 2014, and then this one just last week.

Interesting enough, the CEL is now off. Can't say I'm exactly mad about that... I haven't run a scan since I noticed it was off, but will do so tomorrow to see if it still pulls a code.