Help locating vacuum leak

What car and model????????????engine,aspiration?????????

fountainpen sure has a great question!

If you're running rich, you don't have the common vacuum leak. The common leak on 850s and 70s is in the elbow at the end of the intake manifold behind the power steering pump, but not all of them have this.

Oh man, I did forget to mention my car. It's a 1998 S70 T5.

I'm not sure this makes any difference, but for some reas> Michael Chiu wrote:

Aha, there's a clue. An exhaust leak can allow air to be sucked into the exhaust as well as allowing exhaust out. If this happens upstream of the oxygen sensor(s), then the ECU can be fooled into thinking that the engine is running leaner than it really is (too much oxygen in exhaust = lean mixture). Of course there's no way it can compensate to get rid of this oxygen. Check for leaks from the exhaust manifold down to where the oxygen sensors are mounted.

I think you were on the right track in helping diagnose my problems. I took the car to my mechanic today. He did confirm that I had a vacuum leak due to a big hole in a hose. He quoted me $75 to fix it (parts & labor). I asked him if it was a difficult fix, and he said it wasn't really, but since there's not much room to maneuver, he'd have to take out a pump. In a post preceding this, you had mentioned the "elbow at the end of the intake manifold behind the power steering pump".

Should I just pay the $75 and be done with it, or should I attempt to try the fix myself? Can this be done w/o taking out the pump, or would that only be possible if I had tiny hands?

Thanks, Mike

I think it's possible, but I've never actually needed to do it. I think for $75 you should let your mechanic change it, it'll make him happier, and he'll be more willing to give you a fair shake the next time... Think of it as an investment in this mechanic, he sounds like an honest guy.