In the last 1000 miles or so I've replaced plugs, wires, cap, rotor, PCV valve all 3 O2 sensors, fuel filter, air filter, oil filter, oil, EGR tube, cleaned throttle body, cleaned intake, cleaned IAC and replaced gaskets.

I thought for sure replacing the split EGR tube and cleaning would get rid of the P0401 code. Everything else needed to be done anyway.

The P0401 went away for a few hundred miles but now it is pending. The main problem is it spits and sputters at low idle occasionally and acts like it wants to die. At first start up it still 'knocks' like an exhaust leak which I thought was the split in the old tube. The 'knocking' goes away fairly quickly though. Highway speeds seem fine and gas mileage isn't terrible.

When I pull a vacuum on the EGR, it stumbles and I can make it die. From what I've read this means the EGR valve is OK.

DPFE seems to be a common problem. How do I know for sure?
Has anyone else had similar symptoms that a new DPFE fixed?

Could it be the ECT sensor, EGR solenoid, plugged cats? Has anyone had similar problems? If so what finally fixed it? I'm open to any suggestions at this point.
Thanks for your help!

 

Been there! If you remove the dpfe and drill out the rivets you will find it is full of corrosion from the split egr tube .At least mine was. I put a used one on from a 96 sable (same thing)Clean it out or replace it and things should be better. Pat

 

Thanks, I took mine apart and cleaned it this afternoon. Didn't see a whole lot though, a little hardened white crud and some carbon buildup.

After the first drive it seems better, it's hard to tell while the computer is relearning. I'll have to drive it some more and watch codes to see if it's fixed. I've seen enough improvement already, that if it does it again I'll just replace it with the updated version. Thanks for your help.

 

The Knocking could be exhaust manifolds leaking . 6 of the 8 banks leaked on mine! Pasesetter Headers and blow proof gaskets was my fix .Also these trucks are sensitive to plug wire routing . Make shure the wires are not touching each other . There should be a sticker on the radiator support warnning about this. Also don't run the wires over the egr tube . It will burn them . My misfiring was in the wires . The light and bad fuel milage was the dpfe. After going through a tune up like you did ,fixing a cracked egr tube , dpfe ,cap rotor ,filters ,plugs, headers removed the cats, magnaflow 2 in 2 out stainless muffler . dual exhaust in front of the right rear tire my 96 5.0 w/ 156000 runs absolutley perfect with decent fuel milage and lots of power and sounds better than most muscle cars!. I wish you the same! Pat

 

Thanks to everyone's help on this forum, my truck is running great now. Thought I would follow up and say a new DPFE fixed my hesitation problem and CEL.

Cleaning the dpfe may work in some cases, but with the corroded aluminum and worn out gaskets it didn't on mine. Took about 5 minutes to replace with the updated plastic version Ford #F77Z-9J460-AB. No hesitation, no CEL, runs great! Haven't checked mpg yet, but it has to be better.

GRAVEYARDSHIFT: What headers and what did you do with the O2 sensors?

Still have original exhaust. Would love to update exhaust if the muffler would fall off or something rust out to give me a good excuse.

 

I found a set of new Pacesetter #70-1324 on E**Y. Then I bought blow proof gaskets . They fit great but the stock Y pipe only had a 2 1/4 flange to bolt them up.My exhaust was rusted and the converters were pluged so I went to a muffler shop . The owner said he could make duals with a 2 in 2 out magnaflow muffler and eliminate the cats. Cost me $380.00 for a custom welded dual setup . Then I bought a rear o2 eliminator on E**Y and spliced it in . It is a different truck now, sounds like a 5.0 mustang and the power increase was worth every bloody knuckle and dollar.Check it out!Pat

 

Glad to see you got it fixed!! I'm a little late to this post, but I had the same problem with my 96. tried to clean out the DPFE sensor and ended up replacing it as well....problem gone. My 302 used to knock a little from the bottom end, once the oil got hot, but it did have 155k on it. I sure do miss it