97 Mountaineer 5.0
On saturday I noticed that the engine felt like it was missing as I was driving and sure enough the check engine light came on. Got it home looked for a loose vac line or something. Found nothing. Pluged in the code scanner and got P0301 Cylinder #1 missfire. Sure enough there was a spark where the plug wire was laying on the egr inlit tube. Replaced the wire engine is now running smothe. Turn off check engine light, all is good. Untill my wife gets in the car. The cel comes on again. We run the codes and now I have a P0401. The egr seems to be working I hooked up vacume to it and it caused the engine to stall.? any thoughts could it be the sensor. ????

 

It's probably the DPFE sensor... bolts in place with two small hoses going to it (from the exhaust) and an electrical connector. Ford has an updated design for this sensor.

 

Thankyou do you think this shorted out from the sparkplug wire shorting out on this? And I have been driving it with the check engine light on and it is running great, but will work on this tomorrow. I hope this isnt a dealer part.

 

What is the difference in the sensor? I have replaced mine four times and am in need of replacing it again. I looked at a new one and it appears to be made of black plastic instead of metal.

 

Well I have a Feeling that this whole thing happened because the plug that wasnt firing sent un burnt particles past this sensor and that is what caused it. But now that it is fixed it wont tell me. Or I fried the sensor with the short.

 

I don't think the wire had anything to do with it.. just one of those odd coincidences.

If you keep having repeat DPFE failures, unless something is sorting out the sensor electrically (doubtful), there are two likely possibilities:

1> The hoses from the exhaust to the sensor are deteriorating internally, and pieces of the "rubber" are flaking off and being pushed up into the sensor

2> Excessive exhaust back pressure is excessive and the extra pressure, along with the excessive exhaust heat is causing an internal meltdown of the sensor

I've also learned that aftermarket sensors tend to not hold up as well as the motorcraft ones, as most of them are still based on the old design (even if they have a plastic housing instead of metal)

Good luck!