Hello all...I have a 98 F150 4.6with 69k miles. About a month ago i got my first check engine light and took it to Autozone to have the code pulled. They said it was the egr valve with excessive flow. I baught the valve but before i had a chance to put it in the light went off after about three days. I decided to install it anyway and when i pulled the old one out i noticed that it was different than the new one. So to make a long story short i just cleaned the old one then reinstalled. Since then i get the check engine light every three to four days and it usually stays on for two days then it starts all over. I am getting a little rough idle when i'm sitting at traffic lights other than that everything else seems to be ok. Thanks in advance...Dave

 

DPFE sensor.

Ford has had lots of trouble with these. check for a TSB, and maybe a free fix.
Also the tubes were it located are prone to carbonng up as well.

 

The code your talking about is in referance to the diaphram inside the EGR valve, or, a vacum leak. Check all your vacum lines, even a small crack can mess with this thing. Then check the egr valve position sensor. If no vacum lines are broken/cracked and the sensor is fine then deffinatly go ahead and replace the valve.