Hello. I regularly get white tracking buildup on the contacts inside a new distributor cap after seven thousand miles. The car runs lousy, especially in wet weather. So, I sand off the deposits and the tip of the rotor and it runs good for another seven thousand. Then I'll put on another new cap and rotor, and the same thing all over again. The tracking is even among the four contacts.

The owner's manual says to change spark plugs every 30,000 miles. I assume that is also the schedule for new dist cap and rotor. Mine would be lucky to go 8,000.

I thought electronic ignition was supposed to avoid these type of problems. Could I have a problem with a component in the system? Does anyone recognize this problem? Thanks.

I know this answer is opposite to the advice you have gotten so far, but it sounds to me like you do Not have enough resistance in your secondary ignition system (coil wire, plug wires, spark plugs). Without enough resistance, metal is transferred more quickly from one contact to the other under the cap because amperage is increased. This would be the buildup you are talking about. Using non-resister spark plugs along with non-resistor wires could possibly cause this aggressive metal transfer.
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'89 silver 244DL in Milwaukee WI

That does sound unusual, and there aren't many variables that could affect it.

How old are the wires. The coil tends to make as much spark as it needs to get to ground, so if it sees high resistance anywhere, I would expect that the spark under the cap to be 'hotter' than normal. Just a guess.

If this were 40 years ago, I might suspect that the coil was wired backwards and the spark was actually traveling through the system the wrong direction. That would make the plugs erode oddly as well as the cap and rotor. When that occurred on an old points system, the car would have chronically weak spark, which would cause it to run poorly, especially at high RPM. I don't think that is possible on this system, though.

New plug wires OEM 30,000 ago.

Go to very dark area and look at spark plug connectors, wires, and coil for sparks jumping. I found a bad wire on nearly new set(1000mi.), it was arcing (flashing) inside of the resistor cap for the plug. The wire looked new on the outside. It
caused arcing on top of the coil to the ecu and bat wires which affected running.
There is a light show visible inside the distributor cap no matter what.
Larry
Measure the resistance of the plug wires about 4 to 6 thousand ohms.