[Wheelgenie]

Hi, my 320d auto touring has developed a rather lumpy idle,when its cold and you put it into drive and touch the throtle the revs drop to about 500 for a second or so and then back up. When it gets warm and idles in drive it then runs lumpy as if its only running on 3 cylinders but drive off normally and its fine until you come to idle again. Anybody got any ideas?

 

[ak186]

does it smoke alot?
Poor fuel Consumtion?

Could possibly be leaking injectors

 

[Wheelgenie]

it did smoke but it went in for a new glow plug and that sorted that problem as for fuel economy averages about 44mpg via the on board computer.

 

[SlowTech]

Have you looked through the forum for MAF sensor faults, or have you already excluded that?
these guys sell them, but there is a symptom write up a the bottom of their web page here, sounds very similar to what you're experiencing.
Also you can do a quick check by disconnecting the MAF sensor and the car runs ok, you know its that!

:thumbsup

 

[sdp]

I'm no mechanic but how could a (single) faulty glowplug cause smoking? As long as the car was starting the glowplugs are never used after cranking unless I'm mistaken!

I would guess injectors or MAF, having the fault codes read may help steer you in the right direction so to speak