91 mitsubishi mighty max 2.4 won't start?

Hi, I can't start my truck. After changing the spark plugs, I drove 80 mi round trip. The next morning the truck ran for half a mile before dying. After many attempts at starting the motor, the catylidic conv. was smoking from under the cab of the truck and was glowing red from heat. I've towed it home, recharged the battery, and attempted to isolate the problem. After confirming that it had spark, I pulled the fuel line at the rail and insured that gas was making it there. I pulled the plugs and they appeared to be extremely blackend with soot and slightly “wet” with either oil or fuel. After cleaning the plugs, I again tried to start at no avail. At which time a new noise began in the engine compartment. A small electric switch with air tubing leading to bolth the top of the fuel throttle body, and to a egr looking component on the left side of the engine, began to make a fast clicking noise. Which since continues if the ignition is on. I know that all of these components and sensors are reliant upon each other. I can't afford to purchase every possible part that is possibly responsible for the problem. I not only don't know what's all to check, but also how to check those things.