I just bought a 69 280SEC, looks to have been a very well taken care of car. I was told it runs very well, but closer inspection proved it to be a very rich running car. Gas in the oil , blowing smoke on acceleration ect. Timing is set at 4 degrees ATDC. At speed it runs well, but use a great (10mpg) amount of gas. At idle, the engine surges , rpm's fluctuate between 800 and 950. What adjustments can I make to lean her out? I do not think this is an ignition problem. The car did have a coil contact problem but I have fixed it. New plugs, wire set, ect.