Chrysler Repair: Engine stalls after driving several hours/wait few hours, obd ii code, independent shop

Question
QUESTION: I can drive my 1997 town and country mini van for maybe 50-150 miles, then with no warning, it begins to sputter come to a stop and eventually dies.  I have to wait maybe 2 to 3 hours before it can go again normally, only to do it again????
ANSWER: Hi Russ,
I suspect that one of the two sensors for the ignition cirucit is breaking down as it heats up which is a common characteristic with these solid state electronic parts at the end of their useful life. I would suggest that you do a readout of the memory of the engine controller using a code reader. You may be able to get this done for free at an Autozone store, or for around $40 at an independent shop. Either code 0320 or 0340 are the two sensor codes, but any code that reveals an engine control fault would be helpful in solving this. Let me know the engine and I can tell you how to replace it yourself.
You might try using the ignition key to get the readout: on-off-on-off-on and leave on, doing that in 5 seconds or less elapsed time. Then watch for the check engine light which is remaining 'on' to start to flash, pause, flash, etc. Count the number of flashes before each pause, then repeat and let me know the count results. If that doesn't happen, then watch to see if any four digit numbers appear in the odometer window instead of the flashing, and if that doesn't happen then a readout with a plug-in reader will be necessary. '97 was the first year of the OBD-II code system so I am not certain which way will get you the fault code, but one way or the other once you get it you will likely have the solution.

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QUESTION: Ok...I had it in the shop.  I did the on-off on-off on thingy.  The code was 12.  I did it twice to be sure.  I found out that it means the computer probably was reset, or battery disconnected.  So I am probably going to have to either drive it till it does it again, or proceed with the sensor replacing.  Could you give me some instruction as to costs of the 2 sensors you mentioned and how I might be able to replace them myself....thanks again

Answer
Hi Russ,
I would be reluctant to replace the sensors until I got a code of some sort: code 11 for a crank sensor, code 54 for a cam sensor. The sensors run between $40 and $80, but check with a parts store.  Because you didn't tell me which engine (there are three types possible) I can't be specific about how to replace them, but it is really not difficult at all. Without a code, I would not replace either sensor.
The other item that might cause this problem is an exhaust gas recirculation valve that might be stuck ajar. I would suspect that if the sputtering began when you take your foot off the gas pedal, but not if it began when you were cruising at a constant speed. That valve is located in a pipe connecting one of the exhaust manifolds to the intake manifolt near the throttle, and it has a stem in the shroud area between the body of the valve and the vacuum actuator. The stem has a slot that you can insert a screwdriver tip into and then lever the valve back and forth. It should close firmly via spring action. If not, then spray the valve stem where it enters the valve body with penetrating lubricant such as WD-40 and work the stem open and closed to free it up, if you find it to be sticky.
So check that out and keep checking for fault codes. Then write back when you have a code other than a 12 and tell me the engine that you have.
Roland