Chrysler Repair: 1991 Chrysler: Check engine light- response?, chrysler new yorker, light response

Question
My 1991 Chrysler New Yorker's "Check engine light" keeps coming on after it has been running for a couple minutes, but not all the time. Took it to the repair guy, he says he would have to catch it in the act in order to be able to diagnose it.

Answer
Hi Marilynn,
You don't have to catch it in the act. In all likelihood the engine computer has recorded a fault code when the light comes on and stored it in its memory. Use your ignition key:"On-off-on-off-on and leave on" doing that in elapsed time of 5 seconds or less. Then watch the check engine light, which remains "on", to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat to assure that you have the number of counts accurately.
Then group them in pairs in the order of appearance to form the 2-digit fault codes. The either write back or go to www.allpar.com/fix/codes.html for a list of the codes.
We can go from there.
Roland