Hi,
I have a 96 W210 E230. It is a 4-cylinder 2.3 German Version.
There are times when the car is parked on an incline, the car does not start. The battery and starter turns fine but it doesn't start. What I do is that I lock the car, leave the car and wait for a few minutes then the car will start normally.
There are also times the idling becomes too low and suddenly dies. But at least it starts again.
I just changed the fuel filter. What are the probable cause?
Fuel pump? Relay? wiring harnesses? Dirty fuel tank? Fault in the immobilizer?

Thanks for any info.