A little background...1996 302 OBD2. Bassani headers and wye pipe into single 3”, free flow muffler. My DPFe sensor checks out good for voltage (over 4) with a vacuum hooked directly to the sensor, but when I hook the hoses to it and apply vacuum to the EGR line, the voltage is only about 2.2 volts. Before I remove the plenum and replace the EGR to intake piping, is it possible the free flow exhaust doesn’t make enough backpressure for the sensor to operate properly? Symptoms are strong unburnt gas smell out of tailpipe, poor gas mileage, no CEL or codes stored. Just remember OBD 2 on this one. 1996 is the first year for it. Thanks.