Chrysler Repair: 89 Chrysler Dynasty keeps stalling while driving, diagnostic capability, engine controller

Question
Our car (1989 Chrysler Dynasty)keeeps stalling while we're driving. It starts right away when we start up the car again. Do you have any idea what type of problem this may be? Many Thanks - Lesley

Answer
Hi Lesley,
Fortunately the car has a self-diagnostic capability built-in to its engine controller. It codes faults that it recognizes as two digit numbers (from 11 to 55). So the first thing to do to figure out your problem is to get the fault codes, if any, that are stored in the memory:
Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for either engine and we can look up the possibilities of what is wrong based upon what fault codes you show. But do tell me the engine and transmission type that you have in the car if you do a follow-up question to me.  There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair. Let me know the codes and I can give you some direction. If there are no fault codes then the problem could be a spark issue.
If there are no codes other than 55, you might then put a voltmeter between the + post of the ignition coil and a shiney metal surface (battery "ground") and have a helper try to crank the engine for 5 seconds at the time immediately after it stalls and won't start up (if the problem progresses to that stage). Notice whether the 12v is present for the full 5 seconds, for 1-2 seconds, or not at all. If the engine always will restart, then this is not a relevant test.
Another possibility is that the exhaust gas recirculation valve is sticking open when you take your foot off the accelerator to slow down. If that happens the mixture will be too lean and the engine will stall. So notice if that is the circumstance under which the engine stalls or not. Let me know and I can tell you how to locate and lubricate the valve stem.
It is always possible that the ignition switch is flakey. You could try wiggling the key in the several possible directions to see if you can generate a spontaneous stall by the means.
So those are a few possibilities to look into.
Roland