Engine missing after left sitting
 

Hi All, this car is a 1993 500SL with only 23,000kms on it. Ran fine when I got it and still does if I drive it every day. However if I leave it sit for more than 3 days, it runs very rough at idle and misses badly for about 20 min when started.

It warms up in 10min so I don't think it is temperature related.

Somebody said stem seals but there is no white smoke at start up. It has been suggested to change the coils. I have changed filters and run injector cleaner. If anyone has solved this please let me know. I took it to the dealer the other day while still missing a bit (mainly at idle) and they put it on the computer but said it was fine aaarrrgghh

Any ideas much appreciated.....

Inspecting the distributor caps for moisture & "GREEN" copper corrosion is the starting point that I would try.

i had the same problem and it turned out to be a cracked distributor cap and crappy plugs. hope this helps.

So funny! I thought you were going to say that you left your car sit for a while and someone stole the engine out of it.
It probably is a spark thing but if it's not, it could be water in the fuel. It might be worth draining and refilling.

look in the distributor too!
 

I had something similar a year ago. Car started fine, ran for a few minutes, then would run like a pig, conk out, and not start again for about 20 mins, then it would run fine. This all happened after the summer, and a period of very wet weather. I removed the distrib cap (which was replace recently) and it was in horrible shape and very wet. There is a rubber seal in there which was not making contact and sealing properly. I got some RTV and effected a quick repair and the car runs nicely ever since. However next time the distributor has to come off it'll be a bit of a mess, and I have to find some proper rubber to use as a sealant.