Ford Repair: 98 ford ranger wont start, air control valve, ranger xlt

Question
my 98' ranger xlt 4cyl. was running fine the other day when i parked it and today it will not start. It cranks but won't catch. Everything under the hood 'looks'ok.Wiring, sensors, fluid levels etc. I need an air filter and I think I can hear the fuel pump prime when the ignition is switched on (very subtle "electric click" under the hood?). A while ago I had what I thought may be an o2 sensor problem (the idle was sticking for several seconds at a high rpm when the motor was warm and I sometimes had to use the break in low gear while coming to a stop to slow it )but the past 2 months it has gone away. where do I start.

Answer
check the idle air control valve may be sticking shut, it is close to the throttle body. Try pushing down on the gas pedal 1/4 to 1/2 way and crank it over to see what happens. If it starts and stays running that way replace the valve if not let me know, Also check to make sure you have spark  Thanks Tony