I discovered what the problem was and the cougar now is running way better than it ever has. I just want to say dont fall for the DPFE/ EGR bit.
IF your MPG have not totally bottomed out it's not the DPFE/ back pressure sensor. The chance of a EGR going out are slim.
IF you are getting code P0401 thats egr insuffcient flow and means exactly thats, it's a insuffcient flow.
Meaning pull the throttle body off and clean it. These garages are making a killing off replacing parts that dont need to be replaced < dpfe >
Sooo save yourself some cash and ALOT of stress get the throttle body cleaned right off and a can of Seafoam wouldnt hurt either.
Friday, March 6th, 2009 AT 11:52 PM