Rough Idle and Decreased Mileage

[Pyromed1]

Recently I noticed that my Explorer had a slightly rough idle and the mileage has gone down a bit. I've been told it might have something to do w/ the EGR valve or one of the related components. I do not get a check engine light and I don't have any other symptoms. It has 80,000 miles on it. I want to check the EGR system but I don't know where to find it.
Please help. Any other thought appreciated.
Thanks,
Corey

 

[mrboyle]

The rough idle could be due to several things, including the EGR valve (it should set a code though). The first place to start is (if it hasen't had one recently) with a tune up. Also replacing the fuel filter might help (if it is over 1 year old). It is also possible that the O2 sensors are not reading properly. Its hard to pinpiont a problem untill all the basics are covered.