Hi. My 2005 Sport Trac doesn't start. It cranks, but spark isn't finding fuel. First, history: Radiator went out, so I installed new radiator, water pump, and thermostat. Started the truck up, it ran rough, and died. Started it up again, it ran fine, went to town. Started it up at the store, ran alright, came home. The next day, wouldn't start. Now, I've replaced the fuel pump and fuel filter, and checked for fuel pressure, which I have. I've also checked for spark, and I have it, so it's not my distributor. Additionally, the fuse for the injection system isn't blown. Finally, I've read comments in various places about O2 sensors causing a vehicle not to start, but I have a hard time believing an 02 sensor would make fuel and spark fail to catch. I can absolutely understand it causing it not to run, but the ignition should still try to start the truck. Any ideas of what to look after next?