Hi All,

Today, I got to enjoy the Bob Ayers DPFE experience I also got my first CEL since I have owned my 2000 Ranger with 62000 miles and the 3.0L FFV engine.

I was on vacation for a week after Thanksgiving, and I changed the oil the following weekend. But when I went to drive it, it acted weird. Idled and cruised ok, but when you lifted your foot a little and coasted, the engine would stumble and buck a lot

I thought I had knocked a hose loose because it acted like a small air leak. But I couldn't find anything. So I decided to just drive it and see what would happen. It slowly got worse and finally threw a CEL today on the way home from work. I stopped by AutoZone to get the codes read and it showed P0402 - EGR Flow Excessive. I knew from these forums how many DPFE failures there have been, so I found the DPFE test procedure at the top of the forum.

I checked the voltages on the DPFE sensor (KOEO) and sure enough, VREF was good at 5V, but DPFE SIG was .12, instead of .8V to 1V like it is supposed to be. Totally bad So I picked up a new one for $45 at AutoZone, and put it in with new hoses. The old REF hose and the sensor were almost totally plugged with this hard, crusty gunk. This is probably what corrodes the sensor and kills it.

Reset the computer, cranked it up, let the idle settle down, and took it for a drive. Problem solved! No more CEL and the engine is nice and smooth in all power ranges again

 

Glad to hear you fixed the problem.

You saved plenty by diagnosing and repairing it yourself.