Hoping you can help.

2004 XC90 120k.

Was driving and then pop/quick whoosh sound. No more power when giving gas and has a throaty air sound under the hood. I stopped and for a few minutes car would idle fine. But quickly turned erratic and shut off. Would just keep stalling on start. I unplug the mass air sensor and idles perfect. But approaching 3000 rpms i hear the throaty air sound like when you open a carburetor flap too much and there is too much air/fuel mixing. Plug in the mass air sensor and stalls immediately.

I replaced the mass air meter/sensor and to my amazement, exact same issue still.

On one thread I read about possible crankcase clog causing this. When I cleaned oil trap, the lower output to the crank was 3/4 blocked with hardened debris. I cleaned it out so I wouldn't think that was the issue but possible inside where I could not see I suppose it could be clogging? But the issue sound air related. And why would plugging in my Mass air sensor kill the car?

FYI Engine code reads out mass air sensor code (do not have exact in front of me) but I am not sure that happened before I unplugged it. That is the only code I got.

Any help is truly appreciated.

just replaced timing belt, plugs, top motor mount, Mass Air Sensor, cleaned etm and pcv system,

 

Check for a vacuum leak. It would have to be a big one. Make sure the charge air hose is connected to the throttle. Make sure that if your fresh air pipe assembly has the air baffles, the one by the upper engine mount didn't crack when you put the pipe on.

 

Thanks for your feedback. I fixed it this morning and am just now getting to the forum to update, but I think you got it with "Make sure the charge air hose is connected to the throttle."

It was the pipe/hose connecting to the throttle body. It must not have been put on all the way and so it popped off. Hence the pop/whoosh sound I heard. When I fixed it today I can see how the mechanic didn't get it on all the way. As soon as you start tightening the fitting the one side of the pipe pulls off the throttle body. So you really have to hold the pipe/hose while tightening the fitting the whole time.

Now I understand why the ECU didn't notice the issue until the Mass air flow sensor. But still, I can think of a few checks that could have indicated a ETM issue instead of the MAS. But then again, I didn't design it or for that matter own my own car company!

Thanks again for your quick help!

PS Anyone need a new Mass Air Flow Meter with Sensor? ;-)

 

That's why I tell people that a code for a sensor does not mean that sensor is bad.

Glad you fixed it though