2000 Nissan Frontier Truck Stalled!

Hello, I was driving my truck down the road when the "service engine soon" light came on and the truck stalled. The engine turns over but will not start. The fuel pump does work and I changed the fuel filter. The oil and transmission levels are fine. I checked the distributer cap. There was a little build up on the contacts which I scrapped off. There is no excessive moisture under the hood. I purchased a Chiltons manual and could find no reference to the service engine soon light. Any information you could give would be awesome. Thank you in advance, Gary.