1964 MB 230SL engine will start and rev up but when I lighten my foot off the gas, as soon as the RPMs get below 2000, the engine dies. Here is the rest of the story. About a year ago after not running the car for a while, it would not start. I noticed that the gas in the tank was murky with rust. Pulled out the tank and eventually decided to replace the tank. Did that but the engine still would not start. Checked the injector pump and it was not pumping much. Sent the pump to Gus at Pacific Fuel Injection and he rebuilt the pump. Got the pump back, installed it and the engine started but would not stay running below 2000 RPM. Took the pump out and sent back to Gus. He check and said it performed perfectly on his test machine. o, I have replaced the fuel tank, the fuel filter many times, put in new injectors, spark plugs and the fuel pump even but still have the problem. Hope someone may be able to provide some insight and possibly solutions. Oh...the engine oil is starting to smell of gasoline. Also, I thought it might be the cold start valve but I blocked off the fuel line to it but the problem continued.