Chrysler Repair: 1999 LHS Stalling, blade tip, philips head

Question
I have a 1999 LHS that has began stalling (three times in four trips over 70 miles).  The car loses engine power but not electrical power and stops completely in a few seconds.  After the car sets about half an hour, it starts back up with just a little sputtering and then and runs smoothly until the next stall.  Two different dealerships have run diagnosic tests but could not get any codes or recreate the problem.  There does not seem to be a cooling system issue.

Answer
Hi Richard,
Stalling without any fault codes is always a challenge. It prompts one to think about what units are not monitored by the engine controller or perhaps where the unit is monitored but the malfunction is not bad enough to pass a threshold to set a code. One thing to consider is the possibility that the spark coil pack is breaking down when it gets warm. You would need to check that at the time with the help of another party to operate the starter while you make the observation. You can either carry along a spare spark plug and remove one of the insulator caps from a plug on the engine, insert your spare plug, then holding by the insulator press the threaded end of the plug against the cylinder head and watch for spark or no sparker when your helper tries to start it. Another way just uses a screwdriver with an insulated handle:
To test for spark, remove a cap from one of the spark plugs by holding on to the connector cap and pulling on it (don't pull on the wire). Then use a screwdriver (a philips head is better than a flat blade tip) with a plastic handle to probe inside the cap so that the tip touches the internal wire deep inside which normally touches the tip of the spark plug. Then hold the screwdriver by its plastic handle in one hand and the cap in the other hand so that you maitain the connection between the internal wire and the tip of the screwdriver. Move the assembly to be within 1/4 inch of a main metal part of the engine such as the cylinder head. Have a helper then try to start the car while you hold that position of 1/4" distance and observe whether during the cranking a spark jumps between the shaft of the screwdriver and the engine metal surface. Let me know that test result.
Another possibility is that the fuel pump has cut out temporatily: you will notice that the fuel pump runs for a second or so when you first turn the ignition switch to the run position. The next time you stall see if the fuel pump can be heard to operate like normally or not.
Your stall-recovery symptom is often the early stage of a breakdown of one of the hall effect sensors of the cam and crankshaft position. But it should set a code, unless the failure was enough to cause a no spark, but not so bad as to set a code. So if you don't get spark, I would also look at the sensor signals with a voltmeter, which I can tell you how to do.
Those are the main possibilities. Let me know what results you get the next time you have a stall. If may be necessary to get a OBD-II code reader so you can look for the eventual appearance of a fault code that tells for sure what is wrong.
Another possibility is that the egr valve is hanging up ajar which messes up the mixture for idling. You would notice this if the stalls were always associated with decelerating with your foot off the gas.
Those are some ideas. Let me know which engine you have in the car when/if you write back.
Roland