Hello,

You will find some oil in the intake of a 240 coming from the flame trap. First of all if you do not know the car history, clean the flame trap right away. They only cost like $2.50 so after a couple of cleanings I just stick a new one on. Synthetic Oil is supposed to prevent the oil from collecting. I just started using a Synthetic Blend on the last oil change so have not seen it with my own eyes.

On the surge in the idle, check all the vacuum hoses. A car of that age will often have rotten vacuum hoses. Then you may want to take a few drops of light oil and lube the Constant Idle Motor. That motor comes on and allows enough air for the engine to idle when the throttle body closes. Follow the hose from the other side of the intake where the flame trap hose comes in and there it is. Some of that old sticky oil could have worked it's way down there and be causing the idle motor stick. Another thing to clean is the vacuum orifice on the top side of the intake manifold. The small vacuum line from the flame trap connects there. Take a good stiff paper clip or solid wire and really clean out that small opening. Check all the vacuum and intake hoses going from the AMM, the flame Trap. and those that connect to the intake manifold for cracks or holes. Check the air intake hose from the AMM to the Throttle Body, you will often find holes and cracks in those folds, age and oil are factors. .

Sounds like you have a nice low mileage find there,

Good Luck,

PT