Have vintage 1978 Mecedes 280SE, six cylindar gas. One has to really love these old ones to own one.

Problem: When the engine has been running for a while, it begins to sputter and losing power. One day when hot I drove from Tampa to Sarasota. Threequarters of the way there, it began to sputter. If I turned it off and let it rest, often it would be better for a while.

Later that evening after it had rested when I returned home in the cool evening, no problems at all.

So far have replaced the fuel filter, spark plugs and spark plug wires to no avail. My mechanic thinks it is electrical. I think it may be fuel system related.

Anyone have some thoughts?