I've got a 1984 240 DL on which I've replaced the fuel injection water temp sender and checked around for vacuum leaks (one hose was cracked into two separate pieces, but is now replaced). It's still got an intermittent problem with dramatic surging on cold start, dying as I approach stop signs, etc. It seems to be ambient-temperature-related, being more prominent when it's cold out, and generally lasts for just a block or two of driving, after which it goes away.

I replaced the fuel filter less than 10,000 miles ago. It had gone away after I replaced the broken vacuum line, and suddenly reappeared when I filled the gas tank, so I thought maybe the gas cap underpressure vent was clogged and the tank was developing a vacuum; however, a "street" test of the gas cap (unscrewed it almost all the way) showed that this wasn't an issue.

I'm thinking next, when it's not raining elephants here on California's north coast, to check the resistance on the brand-new fuel injection water temp sender, and then check it again at the computer terminal connection, to test for either a defective sender (the parts house from which I bought it, although they sell Beck Arnley and Volvo labeled parts, often in sealed plastic bags, somehow seem to jinx electrical parts) or high resistance in the wiring.

Any other ideas?