450SEL m117 engine
I have a 1974 450SEL with electronic fuel injection. Car starts fine, runs at 2000 rpm, blip throttle revs drop but dont settle to steady idle. Engine revs up to 2500rpm then cuts, drops to 500rpm and catches and revs to 2500 rpm again. If I blip the throttle again the engine will rev to about 3000rpm and stay there. Have I lost a temperature sensor? Is the cold start valve stuck on? How do these things measure air flow? The Haynes manual is as much use as a chocolate fireguard. Any ideas of what to check first would be gratefully received. Any ideas of where I can get an engine manual with ignition info would be a bonus. Thanks .