I had a similar problem on my 01 just a couple weeks ago - mine just showed up one unannounced too.
My code was just a misfire on cylinder 2. The issue was a bad coil pack. The coil pack would have a very small arc between the connecting "cup" thing on the coil pack itself for cylinder 2 and the wiring harness plastic covering piece. Freaking hard to describe without a picture... but anyway. It was the coil pack for me.
Check the usual stuff: plugs, plug wires, make sure all your sensors are connected properly (mine shook loose a few miles down the road), especially the one on the back of the coil pack.
after that you gotta move on to the o2 sensors & injectors i would say.
--01 Edge 2wd 4dr supercab--4.0L SOHC--31 BFG A/T ko tires--15x8 KMC XD series Assault wheels--Gibson swept Side exhaust--K&N Filter--carriage works black billet grille--speed fantasy black headlights--Blacked Taillights--bumper mod--Cranked T-bars--Rancho RS5000 Shocks --Tint--Blue Gauges & HVAC--and a System to go with it all--