could i have a Bad EGR Valve?

[648372627]

i have a 1997 dodge avenger ES with a 2.5L v6. im wondering if my EGR Valve could be bad i get about 14mpg on gas. my car has a poor idle but will not stall idle gets kinda bad if the airconditing is on. I did a complete tune up and yes it was done right. and i changed my Idle air control valve. after i changed the valve i drove a few miles and i got a check engine light for insuffecient EGR flow but then it went away and never came back. I took the valve off and cleaned it with carb cleaner. im trying to find out why my ide is kinda poor and if the car sits a few days it takes a little longer to start.

my motor has 142k miles but has been properly maintained.