One problem related to gas recirculation valve (egr valve) has been reported for the 1999 Ford Econoline. The most recently reported issues are listed below.
My Ford e350 1999 made a loud flapping noise as I was leaving my home. I pulled right back into the driveway and shut off the engine. I found out that the #2 spark plug had completely blown out of the cylinder head. This has never happened on any vehicle I have ever owned. I take good care of my vehicles. I am a mechanic, and former jet engine mechanic also. My obdii confirmed a misfire on cylinder #2 that is how I located which plug it was. Ford said it would cost $260 to look at it, and up to $1700 if they could repair it. Plus towing. I asked how much a new engine would cost since the van is in excellent condition. Ford said it would cost $7,200 for a new engine. This van has cost more for repairs than any vehicle I have owned in my life. I am 62. Air conditioning compressor $700. 00 coil on spark plug $130 abs brake sensor $138. 00 flex plate and flywheel $700. (caused by loose ignition switch) egr black box $400 replacement. Ford wanted $100. 00 to change my fuel filter. I went to the store and bought the special wrench for $16 ,did it myself in 15 minutes. Recall for wiring near the master cylinder that could catch fire, 1/2 days wages lost. It took me 4 hours to change spark plugs. It was the worst design I have ever seen. A nightmare to get to the spark plugs. I sold the van for $500 tonight. Glad the nightmare is over.