My dad have a 1993 s500, only 70k when we brought it, is 90k now. It is in perfect condition, everything is good except for this ASR problem occured few weeks ago. While we were driving to SF, the ASR turned on, and my dad said the car have no throttle response. It wont accelerate no matter wut. It was at night, so lights are turned on(maybe cuz of OVP?) it could't be heat related problem because the car only been driven for 30mins at the most. We solve the problem by tunring the car off(still going around mph) than we turn the car back on. After that it was fine the whole way(12hour drive). And today the problem occured many times on our way to LA(2hour drive). After many ASR moments, engine check light LIGHTED UP! What are some possible cause of this problem? What are the solutions? Where is the speed sensor, how do they look like? Where is OVP, and wut excatlly is it?(shape size location). Thank you, and any feedback will be greatly apperciated.