i know it is insufficient egr flow but what do i do. what is the most common problems.

 

Any follow up to this? I have the same code as well as the lean banks for both sides. I replaced the EGR valve and cannot find any obvious vacuum leaks.

Thanks.

 

PO401 is usually related to the dpfe sensor.

If this is the only code showing related to the EGR, most likely to be your DPFE sensor. its faulty issue from Ford.

I had to replace mine, after i cleaned, spit and polished my EGR system only to still have the code.

I"ll bet its the DPFE sensor, and easy to install. But clean your EGR while yur in there.

 

This is where sea foam really helps clogging in the first place.
While you have your egr off inspecting & cleaning push a stiff wire in the port holes to make sure the end of the holes into the throttle body aren;t clogged shut with carbon, if so pull off your throttle body & clean it from the inside. (don;t spray cleaner down the throttle body & hope it works). It is easy to remove, clean & re-install.

 

Thanks for the tips. I'll give the DPFE a try since it's not that expensive. Th light for this has been on for a long time.

I did notice when I spray starting fluid in the general direction of the intake the RPMs jump a little bit. Hoping that doesn't mean it's the intakes.

 

i cleaned the ports where the hoses are for the dpfe sensor. no more codes.

 

I will definitely try that!

 

I had a p0401 code on my 2002 4.2l
p0401- insufficient flow...
I took out the egr valve for inspection and it appeared charcoal dirty so i cleaned it using brake cleaner. Put it back in (changed the gasket). Reset the code. But about 15 miles, the check engine light came back so next i did is to change the dpfe sensor. Check engine light never came back so problem was the dpfe sensor.