I've been screwing around trying fix my idle surge and terrible gas milage for quite a while now. I was getting an EGR code and a Running Rich code. Without much thought, I replaced the EGR valve and the O2 Sensor. The problem did not go away. After reading a few posts (from UncleDon and Taylor). I realized that it could be a fuel pressure problem. I bought a Fuel Pressure Gauge and a book that tells you everything you want to know about the Ford EEC IV System (it's a great book and is available on Amazon.com). I've learned a lot from this book. After reading the book, I tested the fuel pressure: It was about 40psi with Key On Engine Off (within spec), but when I started the engine, the Pressure Pinned the gauge (indicating a bad Fuel Pressure Regulator). I replaced the Regulator (very painful to remove those 3 screws) and EUREKA, the idle problem is gone! I highly recommend buying a fuel pressure gauge, vacuum gauge/pump, and this EEC IV Book for understanding how to diagnose and repair Broncos. Thanks for the help, guys.