Okay, so here's the skinny.

'01 v6 pops up with error code p0401. Checked the hoses, they look good. Checked the vacuum pressure, it's good. check the resistance to the control, it's good. checked the voltage to the sensor, it's good.

Few days ago, the engine cut out as I was driving, not accelerating or breaking, and the clutch was in, but I hadn't taken it out of gear yet.

Can anyone help me out with what to do next?

 

Sounds like your on the right track. the code is for low EGR flow, so you need to check that the vacuum is actually actuating the egr valve properly, that the egr valve and tube are not clogged.

That said, my wife's 02 Sport trac with the 4.0 V6 has had this twice. Both times it was the DPFE sensor. it had the rev a DPFE from the factory. They have since released a revision B , supposedly due to high failures on that engine. On that engine it's a 5 minute change and the one from autozone has a lifetime guarantee.

 

Yeah, I replaced the DPFE sensor about a year ago, came up with a different error code then. I guess I'll open the connections up and try cleaning them out. the valve is holding a vacuum.

 

keep in mind a stuck valve will hold vacuum, so while you have it off for cleaning go ahead and cycle it with a hand pump.