Engine running rough at idle

[raka]

I have a 94 530i that runs very rough when idle( Check engine light comes on)...clears when I start driving ( check light goes out) but comes back when I stop. I replaced the O2 sensors last year. Any ideas?

[Binjammin]

Do a stomp test and see what codes come out.

[HausBimmer]

The V8s are notorious for leaking air at the oil separator. Probably need to pull the intake to repair. Some people talk about a wipe for oil to test. Error codes relate to injection manifold leak or MAF out of range - do a search and you will probably get a ton of hits. If it has over 100k and this seems to be the problem - I'd do a rebuild on the fuel rail and replace or have the injectors cleaned & new o-rings.

[spankyway]

I had a similar problem on my 740 and it turned out the valve cover gaskets had let oil leak into the spark plug hole causing the plugs to go bad. I also had some "coil connectors" go bad and the O2 sensors went out. Once my indy fixed all that it ran great again.

[courts]

I own a '95 540ia and recently experienced the same problem. Turned out that the valve cover gaskets were leaking oil and it found its way into the spark plug "chambers" on both sides. So I replaced the gaskets and spark plugs and what do you know, she's purring like a kitten again.

[jamesdc4]

to Bf.c.

On the E39s, a dirty MAF or ICV usually is the cause of this amongst other things. I'm still learning about common causes of issues with the E34, so I would default to the more experienced owners of this section.