PO401 code Insufficient EGR Flow

[DailyDriver]

I have been chasing a bad mileage gremlin. I do not have a CEL, but since I'm at my wits end to figure out why my mileage sucks, I stopped by NAPA & used their scan tool just to see if anything showed up.........well this did.

I've read the DPFE sensor could be the culprit, but I'm not experencing any performance issues (stumble or hesitation).

Could this be the mileage gremlin???

 

[shadetree]

DPFE is a common failure. You will never know it is not working by power loss, or by the way the engine runs. I also seriously doubt it causes any mileage problems to speak of as the EGR only works at steady speeds. On my vehicles, it helps mileage on long runs by being disconnected. I am currently testing to see if I have any changes in mileage in everyday driving.

The exception would be with an EGR that is hanging open, then there would be other symptoms.shady

 

[DailyDriver]

Hmmmm, if that's the case I'm not going to worry about this.

Back to square one lol.

 

[slolearner]

Bad Mileage

What do you consider bad mileage?

 

[DailyDriver]

I was getting 21-22mpg. Now I'm getting 17-18.

 

[bluebombersfan]

Daily driver that makes two of us

17-18 mpgs is right were I'm at with my 96 and it's driving me nuts, DId your mileage drop suddenly?
Mine has dropped slowly over the years. Driving in the city is fine on the highway feels like I got maybe 85hp. I used to have knocking issues for a while but I changed my sparkplug wires and it was gone instantly.

 

[DailyDriver]

Some guys here are saying it's the winter blend causing it. But I live in SE Louisiana & have never had this issue in the 9 years of owning this truck. Not saying it isn't the case, but I find it improbable.

It was a gradual loss of mileage over about an 8 week period starting around Sept. or Oct. 2008. Now, no matter what I try or what brand of gas I use it steady gets 365 miles out of a 20 gallon tank when I was getting 425-450 previously. I have zero drivability issues other than the crappy mileage.

 

[bluebombersfan]

If your truck is like mine you won't notice the loss in performance untill you put your engine to the test, try towing something on the highway and it doesn't have to be very heavy,
what kind of mileage do you got?
I'm only at 110 km
I think i found a way to test if the cat converter is plugged not sure, I want to remove to O2 sensor before the cat, I figure if the cat is plugged the exaust will come blowing out of that hole instead of the tailpipe? just an idea