Well this is complicated and has been complexing me for quite awhile. I have a 1984 500sel Euro with 130k. It likes to idle 1grand-1500. When cold it starts right up without a problem. When hot it tends to not wanna start and sometimes needs excessive cranking while the excessive cranking you can smell fuel. Also now it won't hardly run over 70 without cutting out. I put it in neutral when loosing speed revved it up it went to 5 grand no problem then put it in gear and continued home for the whole mile i was away. I have 3 idle control valves. All make the car idle different. Sometimes the car will idle a perfect 700 but rare and only when a/c is on. It has new wires and plugs in it. Also a new distributor cap. It is my 1st w126 and I truly love it but would greatly appreciate some advice or hints of where to look for my issues. I fear all these problems may link to one thing. Also to add i had catalytic converter melt down a month ago and removed the resonators so all it has exhaust wise is the muffler under the trunk. Before removal it wouldn't run over 10 mph and barely kept that. Thanks