Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem
Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing
Saturday, May 28th, 2011 AT 8:26 PM
Just to add to this one if the starter doesn't turn the engine over it's most likely the starter see if your getting power to the small purple wire to the starter with the key in the start position. If it cranks and won't start try checking for spark remove two wires off the coil pack and see if spark jumps from tower to tower. If it doesn't then I would check the crank sensor with a ohms meter when there was no spark. It sticks straight up out of the block with two wires going to it to the right side of the starter. It should have 800-900 ohms value. When they go bad they usually read as a open. If it has spark then try starting it with the gas pedal all the way to the floor see if it starts that way. Let me know what you find.