L400, stalling, black smoke, electrical issues

[claudiadh]

Hi all,

We have an automatic 1999 L400/Chamonix which has the following history of issues:

Since the purchase 4 years ago we have been noticing the electrical is acting up, for example the dashboard clock/temperature comes on and off without any clear reason.

2 years ago we had some starting/stalling issues and we replaced a dried out rubber seal on the fuel pump which was a big job, but fixed that issue.

Recently we noticed something was really off while exhilarating from a stop @ traffic light - as we pull up it seems not wanting to exhilarate properly and have poor power as engine light would come on. A restart would fix that normally and engine light will turn off. This would be happening inconsistently and has been checked out by mechanics who could not give us an answer due to its inconsistency.

Lately we had two significant incidents which involved the car starting fine but at the 3rd stop in town it would buck up like a wild horse, blowing significant amounts of black smoke and stalling out. After the first incident we got it towed to garage and they experienced the issue first hand, checked fuel/injectors/seals etc but no real outcome and after running various tests it started to run fine again and left both garage and us puzzled.

We drove it fine in town for about two weeks, even though you could feel it wasn’t running smooth. We took it on the highway for 2 hrs without issues, but next day the same issue happened with black smoke, stalling and our blinkers somehow stopped working. We were able to drive back and it’s been fine on the high way and we put it in neutral at the traffic lights which it seemed to like a bit better.

Long story short, we can’t figure out the root cause, don’t feel it’s reliable enough to drive it anymore and wondering if it’s something to do with the electrical.

Any ideas anyone?
Thank you so much
Claudia