This is just a report on a repair.

1993 245 developed over time a rough idle - bad miss: stalled when started; ran fine - good power, good MPG, smooth. Sometimes stalled hot. Not my car so don't really know course of the deterioration. A friend bought it "needs work" and asked for help.

Reminded myself via search here that symptoms are classic air control valve and/ or fuel pressure regulator.

So in sequence I did the following (none of which had an effect)- changed/ cleaned: plugs, air control valve, FP regulator*. Then I swapped out wires & cap and voila - ran great.

I assume wires were bad (don't know visible tests for good/ bad here) but there was visible evidence of copper corrosion inside the cap terminals and aluminum corrosion at the plug end. It may be that cleaning the terminals would have had the same effect.

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*The FP regulator was not holding pressure and so I thought that might be the problem but it appears not to have been. My 1988 by contrast sat for 3 weeks and had great fuel pressure when I disconnected the regulator.
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240s: 2 drivers and some parts cars