studdering

[mislead]

I have a 1995 540i. It has been studdering at idle. I took it into the shop and they said it is the o2 sensors. My question is how do u know if the o2 sensors are bad or if you have a vacuum leak instead?
thanks,
Ben

[e34.535i.sport]

I have a 1995 540i. It has been studdering at idle. I took it into the shop and they said it is the o2 sensors. My question is how do u know if the o2 sensors are bad or if you have a vacuum leak instead?
thanks,
Ben

As far as I'm aware they'll both throw the same code... Have you tried pulling the oil dipstick/filler cap when it's idling? It should go mental if you don't have a vacuum leak...

[Ferret]

Unplug the plug out of your MAF sensor... if it starts running more smoothly you've got a manifold leak and there's a good chance the emissions plate on the back of the manifold has blown open...

Regular part failure, reasonably straightforwards to change and inexpensive...