Recurring EGR valve problems on 2001 Mazda Tribute

Car began idling rough today; hesitant ignition. EGR valve was sticking. Have replaced the EGR valve twice in the past year and a half. If I hook a vacuum line to it, I can get it unstuck but after a while it will do it again. No engine light indicating problems with sensors, but then again, the thermostat for temp has been lit for about 5 years even though there is no problem with overheating, mechanic told me at that time that he could run a test at the price of about $80 but that it was a common fault on these cars for the light to be on. Got a rebuilt transmission little over a year ago and that seems to be having some minor hesitation shifting from second to third gear at random times. Ideas? Solutions?

Asked by for the 2001 Mazda Tribute
Are you doing the work , or is a mechanic? That will help in how the question is answered.
DIY, as before.
1 more answer
possible clogged EGR ports.