Hello, well my 1997 V90 has developed a problema on recent weeks and I can't figure it out.
Every time I rev the engine it makes like a whistle noise, has troubles to start at the first try and when driving it makes a very loud exaust rumble. I suspect its a vacuum leak but cant find any.
Any help?

 

exhaust rumble? not sure if your model has a flex pipe section in the exhaust, but that's a common failure point on other models. as to the whistle, does it go away if you pull out the dipstick or open the oil fill cap? If so you may have a clogged PCV. If you had a vacuum or intake leak, you'd likely throw a check engine light for a fuel trim issue and would possibly have a rough or wandering idle.

 

I tried running the engine without the dipstick and it didn't stop.
Oh and I forgot to mention the engine os really down on power.

 

you can try spraying around with some carb cleaner on intake air hoses, seams and vacuum lines. if nothing, a shop may need to do a smoke test.