98 Expedition CE light

Hi, I have a 98 Expedition with 166k miles. Since this summer the the check engine light has been on and the shop I take it to has not been able to figure out the problem. It shows the codes that something is wrong with the EGR valves when a diagnostic test is run. So far the EGR valves have been replaced and the ports have been cleaned multiple times, but the light continues to come back and stays on. I have just about given up, as it runs great, and I cannot afford to keep sinking money into it, but I do want the problem fixed. Any advice would be greatly appreciated. Thanks.

Has anyone tested the DPFE sensor?? If it is a P0401 or P0402 have the DPFE tested or replaced.

I had the exact same thing happen a few years ago. I went through a bunch of trouble and money buying and installing EGR related parts only to have a helping hand on this forum tell me to check my vacuum lines under the battery. If your battery has leaked at any time, the acid can fall down and eat right through the vacuum line cluster located beneath it.
That was the exact problem with mine. My code was telling me there was insufficient EGR Flow, and it was true. It wasn't the EGR parts that were broken, they weren't working because there was no vacuum to them making them function. I went and got some rubber vacuum line and repaired the bad sections and solved the problem.

Good luck.

I had the same problem recently, and the replacment of th DPFE did the trick. Also, did a replacment on teh vacumn lines that come to the DPFE just in case while I was there. Good Luck.......