slight engine vibration

[major]

I have this problem with my 95 S500 which the dealer can't seem to fix. When the engine is idling I feel a very slight vibration. It feels as if the engine is mis firing because the vibraion is not constant , but you could feel a slight shaking or shudder as the engine idles. It is not a very noticeable shaking or shuddering but I am very sensitive to it and that is why I would like to correct the problem. The dealer have so far replaced the engine mounts, Distributor cap and rotor and reset engine computer. They have also told me the service rep has checked the car and the shaking is not excessive and within the norm. Any possible solution to this problem would be greatly appreciated.

[Michael]

Is the exhaust system touching the chassis anywhere?

Definitely something to check...had a similar prob with my 500.

[Stan Pittman]

I just finished a major repair on a 1995 S500 where the engine was remove disassembled and repaired. Upon completion of the work the engine shook in the manner I assume you are stating and it turned out to be a leaking fuel injector seal at the intake manifold. It ran perfect except for the miss at idle.

[major]

Thankyou for your inputs. I've been away for awhile and I finally have a chance to read the forum. If you don't mine me asking Stan, Is there a way for me to check on that fuel injector seal leak? Do I need special tools?

[Stan Pittman]

No special tools needed. Just apply some transmission fluid or engine oil around the base of the injector and if it is leaking the oil will seal the leak for a few seconds and probably long enough for you to tell if it makes a difference.

[major]

Thanks Stan, I'll try it this weekend.