1997 Ford Econoline Starts then stalls

I have a 1997 Ford E-150 Econoline Van 4.6 V-8. I just replaced the battery and alternator, but when I went to start her up, the engine turned on for five seconds or so until it idled, then died. It will stay started with your foot on the gas but otherwise dies quickly. What do I need to work on next?

When was the last tune up? May be bad plugs, wires, rotor and dist cap. The Idle Air Control (IAC) valve may be clogged. Chilton's repair manual can help you locate it on your specific vehicle, and give you more suggestions for trouble shooting the problem.