My wife talked me into buying an 89 Volvo 740 turbo for her to use while we're stationed in Hawaii.

It's a nice enough car for the price, and it seems nearly everything at this point has been replaced (according to the exhaustive maintenance records) so I wasn't expecting to have TOO many problems.

Here's the problem:

About a week ago, I noticed that the Turbo got a much higher pitch when it kicked in during acceleration. I just wrote it off as the difference between driving with the window up vs. down.

Unfortunately, yesterday the car quit accelerating with the turbo altogether. I can drive it fine, and it has no problems at moderate acceleration. However, when I take the gas pedal more than about 25% down (to the point where the turbo normally kicks in), the car begins to slow, the RPMs shoot up as they predictably would normally, I hear the turbo wind up, but and then there's just this large whooshing noise. It'll do this until I let off of the gas and then there's a "sneeze" as if pressure was quickly released. At this point, the car's RPM's drop to 1000. After a second or two at the reduced power and 1000 rpm's, I can go back to accelerating moderately.

The car will get up to highway speeds, I just have to do it without punching the pedal at all, as whenever the turbo kicks in, speed drops down to about 25-30 mph for as long as I'm holding the pedal in, and I get the whooshing noise.

I work on airplanes for a living, so I know that what is probably going on is that there's a vacuum and/or pressure leak. My questions are these:

1. Every other FAQ I've read regarding this problem details my symptoms exactly, except for the fact that I never see any black or gray smoke in my exhaust.

2. I DID find a tear in the plastic hose between my filter and some kind of valve. This plastic hose turns into the preheater hose after it comes out of the valve. At least that's what I think it is-- it goes into the turbo.

3. I put a TON of tape on top of the tear in the hopes that that might be my leak, but nothing changed-- still no acceleration.

The turbo was replaced about 9 years ago, and aside from a very minor whistling noise when it kicked in, it hadn't been exhibiting any of the symptoms of a dying turbo, according the guides here and on swedishbricks.com

4. The radiator that was installed a few years ago by the previous owner hangs over the airfilter holder, so I can't check to see if the filter's clogged. A clogged filter wouldn't be cause THIS type of problem would it?

Thanks for any help yall may have!