The only time my '82 quit on me I was on the freeway, coasted to an exit and parked it, towed it home, and then found that I had a bad coil, which took out the ignition control module. The coil was partially shorted internally, found it by swapping it out. You have to be careful with the coil replacments, different years use different coils due to the varying igniton control module designs - some use a 6v coil, some a 12v coil.

__________________
Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C