My 240D suddenly developed a very rough idle. I had been using Power Service fuel additive but had stopped so I thought maybe that the injectors had become fouled. I used some fuel additive thinking that it might clear things up, but it had no effect.
Engine runs OK at speed, a little rough, ( rougher than before) but not real bad.
I adjusted the valves today, but with no discernible effect. It seems that there are brief ( 1/2 second to 1 second) periods when the idle smooths out, but then its rough again. I checked the EGR valve, and when I applied vacuum to the EGR, the idle got rougher and there was more noise from the intake, so I assume that is not sticking in the open position.
Could it be air in the fuel from a leak somewhere in the system? I want to replace the clear fuel lines but could not get any today.
Any ideas on the cause of the rough idle?
Michael
Bel Air, MD