190e stumble

My 1988 190e 2.3 is exhibiting a problem that I can not find a cause for. As the engine heats up it will stumble and light the check engine light for just a second. It happens so fast that if it were not for the
momentary flash of the check engine light you would not notice it. It does it once and then the motor runs along as strong as it always has.
I can not find a problem and there seems to be no pattern to it. It happens at all outside temperatures and conditions. The only thing I can say is that is seems to only happen when the headlights are on - maybe as it does not do it every day so I can not say for certain that the headlights have anything to do with it.
Any ideas out there on what to check? It has delivered 200K miles of good driving and I would like to drive it until spring before selling it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Over Voltage Protection Relay?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.