My cel light comes on for awhile then goes off for a few days. The code read is P0401"insufficient egr flow". What symptoms will I notice from this. The truck seems to run fine.

 

Usually the DPFE sensor is the culprit and is sending bad signals to the PCM -

 

Is there a test for that. I thought I had read somewhere that was a dealer only item.

 

There are numerous posts on checking the EGR system. Ckeck the system first, don't just start indiscriminately throwing parts at it. Diagnose the problem and perform the proper repair. Some engines have problems with the EGR passages in the intake manifold filling with carbon and restricting flow. Every time mine does that I get the light on and off a few times and then I clean the passages and everything is okay for another 70K miles.

 

Increased NOX emissions - important if you have emissions testing in your state.

Your fuel mileage may take a little hit too.

Combined with other things, the engine may be easier to overheat as well. Spark knock or pinging may be more likely to occur.

 

Yes there is - resistance of course , basic testing procedures can be found in the Haynes /Chiltons Manuals.

It may still be a dealer specific item . Ford updated the DPFE and you could only purchase the updated one thru the dealer. I 'm not sure if that's still the case but I would do so anyway..

 

That's the route I would take, too, and I would also change the cats and do the seafoam trick, that should take car of a lot of the carbon buildup inside the engine and help prevent future problems...I would do the seafoam trick before I changed the cats, though, can't be too careful...

 

Thanks for all the replies, I'm going to pull the EGR first and clean the ports, It's got 228,000 on it now and never cleaned. I did the Seafoam a few months back.

 

Your better off pulling the throttle body and elbow - cleaning all the ports in there as well.