EGR has got nothing to do with idle or even fuel which is obviously the problem if it runs on just starter fluid but not without it.
i have a similar issue when it gets cold out it really doesnt want to start i have to turn the key on so i guess the pump primes the lines then i turn it off then on again and it will usually start after that.
somethin to do that might tell us something about whats going on is hooking up a pressure gauge and finding out the pressure at the fuel rail with key on engine off, while starting, and when you get it running, what its doing at idle. i think those might help us
2003 3.8L V6 4R70W
Windstar Upper Intake with cool-air intake, MAC LT headers, BBK O/R H-pipe, and flow 40s, SCT tuner, FRPP Alum. D/S, 3.73 gears, Auburn HP limited slip, and Team Z LCAs, Eibach sway bars.
Best 1/4 time: 15.036 @90.92mph, 2.148 60'