My otherwise faithful 1989 240 has developed a little problem and I hope someone experienced can give me a little help. At higher speeds on the highway, the little red battery light begins flickering and after a few minutes, the gauges also begin to go dead and the car starts to sputter. If I slow down immediately, power is restored, the gauges re-enliven and the sputtering stops. It will then run fine for a few minutes and then aforementioned cycle will begin again. On city streets with stop signs and lights, it runs fine. The problem is on the highway. The battery does not discharge when all this is happening but the electrical power begins to fade at consistently higher speeds until I slow down or stop. I suspect a voltage regulator issue or possibly a short? It is obvious the alternator is charging the battery but something is interfering with the electrical system at higher rpms. Any ideas from you electrical troubleshooters? Denis in Tucson, AZ