Strikes me as rather odd, this one, but possibly someone on here has had the same problem. The car is a 1994 SL500 - M119 engine, old hydraulic four-speed auto box. Engine and gearbox warm. The car started fine, but the throttle seemed rather flaccid - plenty of travel and nothing, then it came with a rush (quiet in the cheap seats there...). It was idling at just over 1000 rpm, whereas it's normally 600 rpm in N, just under 500 rpm stationary in drive. Driveable, but odd, so set off for home - 10 miles motorway, a mile normal road. On the motorway, it would not change into fourth, however much I moved the lever from 3 to D and back, though otherwise the changes were pretty much as normal. I soon tired of keeping the revs down by trundling along at 55-60 mph among the lorries, so pulled over on to the hard shoulder, switched everything off, then restarted the engine. Normal service resumed. Stopped at Tesco half a mile from home to pick up a few groceries, and when I restarted, the problem had returned - no fourth gear, high idle, floppy throttle. Ladies and Gentlemen, the floor is yours. Does anyone know/suspect what it might be?