"Fred W" > wrote
> bmwguy2 wrote:

>> My car's idle is not stable (it fluctuates b/w 800-1800 RPM) and I was
>> told to replace the O2 sensor and it might fix the problem
>>
>
> It might, but there's a whole better chance that it won't. When O2
> sensors go bad they throw check-engine codes and the car idles very
> poorly, but genrally not where the idle races up and down. Your symptom
> sounds a lot more like a severe vacuum leak. Look around in the ngine
> compartment for a hose that has blow off or cracked or a cracked rubber
> intake manifold boot.

Well, Fred, it's not likely to "throw codes" on a pre-OBD car. ;->
However, I agree about the vacuum leak. Ensure that the oil
filler cap and oil dipstick are firmly seated, too.

FloydR