I have researched through several years of past messages to see if anyone has had this problem but cannot find any. There is some great reading there and I have gleened several new ideals. There are some very smart people here. I have owed this 87' 260E for several years without problems. If I do not drive her for three or four days I have problems getting her to start. When she does she runs funny, like a miss in the ignition. I can drive her three to five miles without incident but once I stop the engine dies. If I catch the failure early enough I can put her in neutral and the engine will continue to run but I must be careful selecting drive again as the engine usually will die. When I try to restart the engine will not fire. I have checked the air, fuel, and spark and all appear to be normal except the spark seems weak. Holding the pedal to the floor results in a flooded heavy gasoline smell. Plugs are wet also. I think she sees me drive off in the other auto and pouts as once she sits for 2-3 hours everything is fine. Starts good, runs good, and does not stall.
Any ideals?

 

Try new spark plugs of exactly OEM brand/type, gapped precisely and torqued evenly at the correct rating. Check the spark plug wires carefully for good condition. Check the distributor cap and rotor. Check the air flow sysem, start to finish. Check all connections on the engine.
Bill Mercer

 

Could be all sorts of things but picking up on your observation of weak spark.

Does your vehicle have a single spark coil and distributor?

Check carefully that the high tension electrical circuit is good by visual inspection. remove dirt etc from leads, carbon dust in distribitor etc. Have a look at the HT leads and distributor etc at NIGHT (dark) to see if you can see any HT leakage paths.

Purely a WILD SHOT but have you considered a bad coil? Have known these to leak oil and give symptoms just like yours.

COULD be plugs but can't think why these would give a problem after 3 to 5 miles.

Stuart

 

I had picked up a maintenance manual from ebay several years ago. Within the manual there is an adjustment for the airflow sensor valve. It involved taking a punch and striking a small dowel to lower the valve to fall within the beveled edge of the sensor. I have had stumbling starting problems since making this adjustment 6-months ago. This past weekend I removed the sensor and reset the dowel pin back to where it was originally. Everything seems to be fine and even runs better at slower speeds but I accomplished a much needed cleaning of the throttle valve and linkage. I have not tested the 2-3 day sit but will keep you informed when complete.
Thanks
Bill