Am trying to figure out which is whichKnow the loction of the egrVacuum line from egr runs to a little plastic thing with a round top on the passenger side of the engine at intake manifold level.Another rectangular potmetal looking thing with 2 lines running into the bigger exhaust source line hooked to the egr is at the front of the engine close to the egrWhich is the dpfe??? and what is the other one?? All 3 seem to constitute the exhaust gas regulator system somehow or anotherI suspect one or the other is causing the high gas consumption and other problemsAny suggestions for testing???The rectangular potmetal looking thing is actually aluminum and it is the DPFE sensorThe best way to test it is to take it to a dealer and have a scan tool hooked to itThe scan tool can provide a voltage reading to tell the technician whether or not the DPFE is workingThis sensor measures the amount of exhaust pressure that is traveling towards the EGR valve, and is a common problemIf yours is aluminum it has not been replaced, the new style DPFE is now plastic, due to the problem of corrosion from condensation in the exhaust, which will cause the old aluminum sensor to failThe plastic thing with the round top is the EGR vacuum regulator, this is in charge of sending vacuum to the egr valve to open it when neededYou really should not see a big change in fuel mileage with a defective DPFE, maybe some lurching while driving, but that still would be mildA trip to see a qualified technician could save you a lot of headache.Other related question