Jim,
I had the yellow "Service Engine Soon" warning light come on (2002 EB, 4.0L SOHC) the other day, along with some very minor bucking, only at part-throttle. My dealership has drive-up, no appointment service, so, later that day, I drove in. Last than ten minutes later, it was fixed.
"2F1Z-9J460-AA SNS ASY EGR PRESS VALVE" was replaced. The the service manager said that the DPFE sensor was not "changing".
I like to think I know a good deal about engine controls, but not this one---it sounds like a pressure-relief valve for the exhaust-gas recirculation, but I'm only guessing. I know you're busy, but if you have a second, could you please tell me what it does?
Thanks!