First lets clear up some terminology so we're both talking about the same things. "Would not crank at all" is a starter problem. The spark plugs and fuel filter aren't even in the picture yet. If the starter is cranking the engine, you have most likely had the same problem all along but you replaced the wrong parts. The place to start is by reading the diagnostic fault codes. Mitsubishi and Chrysler have a lot of things in common but I don't know if reading codes is one of them. With Chryslers, cycle the ignition switch from "off" to "run" three times within five seconds, leave it in "run", then count the flashes of the Check Engine light. You'll get from one to five flashes for the first digit, a short pause, then a series of flashes for the second digit. After a longer pause the next code will flash the same way if there is one.
The most common failure is the camshaft position sensor. The Engine Computer needs to see pulses from it and the crankshaft position sensor, then it knows the engine is rotating, (cranking or running). When it sees engine rotation, it turns on the automatic shutdown (ASD) relay. That relay sends current to the ignition coil, injectors, and fuel pump or pump relay.
Both of these sensors commonly start to fail by becoming heat-sensitive. They will either stop working after the engine has warmed up, resulting in stalling, or they'll fail right after a hot engine is turned off and that heat migrates up to them. You'll have a "cranks / no-start" condition, but it will work again once it cools down for an hour.
To verify the rest of the ASD relay circuit is working, monitor the voltage at the ignition coil or any injector with a test light. A voltmeter will work too but some don't respond fast enough to be accurate. You will see the test light light up for one second after turning on the ignition switch. That tells you the circuit is working and the computer has control over the relay. The test light should turn on again during engine cranking. If it does, and it stays on steady, you have a fuel pump OR a spark problem. Both are relatively rare. Most commonly the light will not turn on during cranking. That's when you look at those two sensors.
Thursday, January 9th, 2014 AT 3:02 PM