I have a 1990 Century (3.3L). Just last night I was driving along and the car felt like it was going to stall and then it continued on at which time the Service Engine Soon light came on. This happend a few times and then did actually stall on a couple of occasions. When it stalled it started right away with no problems. A year ago I had a similar problem and the ECM was replaced. I am hoping it is not the ECM again??? Has anyone else had similar problems. Usually the Service Engine Soon light stays on after there is a problem. This one stays on for 5 seconds and then goes out.

 

If you haven't already, try the throttle position sensor...mine went bad 89 Century, 3.3L and the Check Engine light was intermittent just as you describe...fyi it may only need adjustment.

 

dont replaceANYTHING before getting that trouble code. even if the light goes out, the ecu will store it as a history code. then go from there.