The stalling that began a couple of months ago has gotten steadily worse. Now it occurs regardless of engine temperature or ambient temperature. Mostly it occurs while idling, but sometimes the car bucks while under load, like it's about to stall. My car has the K-jetronic (CIS) injection.

I've replaced the spark plugs and swapped distributor caps with no change. The spark plug wires are relatively new, and the fuel filter has about 11K miles on it.

I've had both the main fuel pump and the prepump fail in the past (both replaced) -- this doesn't "feel" the same -- the engine stalls suddenly, although sometimes the rpm's drop then rise back to normal. If I rev the engine up to say 2500 rpms, it usually won't stall.

Don Foster mentioned the relay on the left inner fender well just behind the battery. However, I see 3 different electrical "thingies" at this location, arranged from front to rear -- which, if any, would cause the problem? He also mentioned a relay above the hood release. I found a multipin connector there, which when disconnected, prevented the engine from firing (the starter still worked).

What about the ignition coil or maybe the ignition switch? Both are original and the car has 236k miles. I've also never had to replace the wiring harness, nor have most of the vacuum lines ever been replaced.

Any help that can be provided will be greatly appreciated!