Chrysler Repair: 99 Chrysler Sebring, chrysler sebring coupe, crankshaft sensor

Question
Ok so I have a 99 Chrysler sebring coupe, when it runs it runs great! but...the problem is all of a sudden, no warning at all, the car will die, and you have no way to know when or if it will start again. Going 65 miles an hour down the road, just shuts off and sometimes will start right back up, sometimes you have to wait 15 min or longer, sometimes days...let's say you park it one evening and go to start it the next day or even a few days later, or even 5 min later, sometimes it will start, sometimes not, no codes come up on a scanner, again it makes no noise, does not drive any differently, NO WARNING signs before it dies, and NO WARNING signs before it decides not to start for however long it feels it needs...HELP?

Answer
Hi Gary,
No start with No codes is a tough one.
The engine controller is not capable of detecting all the reasons for the engine to shut down. For example, there could be a problem with distributor cap or rotor that it won't be able to detect, but you can test for spark at the time of the shutdown and see if there is or is not spark. When it fails to start you can often get to the bottom of the cause, or at least localize it, by doing a simple test or observation at that time. First would be to have a spare spark plug so that you can then pull off one of the spark plug connector caps (twist and pull on the connector proper not the wire) and insert the spare plug. Then find a helper to crank the engine while you hold the threaded end of the spark plug against the cylinder head (holding it by the disconnected spark plug cap) and observe for a spark to jump the gap or not or just for 1-2 seconds of a full 5 second crank. If you don't get any spark then I would suspect the spark coil, rotor, distributor cap or autoshutdown relay. If you get spark for 1-2 seconds I would suspect the crankshaft sensor, if you get full 5 seconds of spark, then the spark circuit is o.k.
Then you can listen for the sound of the fuel pump which will run for 1-2 seconds when you turn the ignition switch from off to run position. If not, then the fuel pump could be flakey, or the autoshutdown relay is flakey. A voltage measurement of the output of the relay to the fuel pump would tell you which.
You could also have a flakey sensor (e.g. MAP) that is not so far out of line as to reach the threshold for a code to be set. That can only be detected by a code reader that has the ability to give you the sensor readings for comparison with what they should be to sustain ignition.
Are you sure that you are actually getting code readouts, or just no response from the reader? About all you can do is start analyzing for spark and fuel pressure, and with a reader the factors that affect mixture AT THE TIME  when the engine won't run.
I wish there were a simple answer but there is not one that I know of.
Roland