Thought I'd post my story .... thanks to the great folks/advice on this forum I got my 1998 5.4 Triton E150 ClubWagon running SMooooth again.

Had the PO401 code and a very ratty running van, at the time did not have a vacuum tester and removed the EGR valve to expect the port clogged. The port into the throtle body was remakably clean. I have 125K on "The Beast"
A couple days later borrowed a vacuum gage and tested the EGR .... the motor fell on it's face with the first squeeze. Tonight I replaced the DPFE with a Ford part as recommended here .... was $87 w/ tx here in central lower MI. Took about 20 minutes to R/R it and she runs great. I am sure the ports will glog in a few more K .......Thankyou all very much.
Harold H.

 

I got a '93 E150 conversion van with 140,000 miles on it a couple years ago. Before I became familiar with anything under the hood, it died and had to be towed to a garage, where they checked it with their computer. Their diagnosis was a bad vacuum part that ended up costing me $300. A few months later it died again on the highway. I puuled the engine cover off and started checking any hose that looked like a vacumm hose. I found one that had begun to deteriorate and was not maintaining a tight fit. With a pocket knife, I trimmed off the end and reinstalled the hose, which seemed to solve the problem. This happened two more times. I decided to carry spare vacuum hose and have now replaced the worst of them. The engine runs like new and has been reliable for at least 20,000 miles.