Volvo Repair: the turbo on my volvo 740 1989 holds back at times, unexpected surgery, vacuum leak

Question
hi,
I buoght a 740 with 164000miles on it. It runs well but at times the turbo doesnt seem to work. The engine shudders when i push the pedal down. But sometimes it does go when high in rpm. if i accelerate slowly no issue but when trying to go faster the turbo holds back it seems.

Could it be the mixture? any other ideas?

thanks.


Answer
  I'm sorry it took so long to get back to you. I had an unexpected surgery and will be out a while.

 What is the boost guage doing when it shudders?
  More than likely, you have either a vacuum leak, or a leak on the pressure side from the turbocharger. Check the rubber boots and hoses from the turbo to the intercooler, and from the intercooler to the intake carefully. They are often cracked or swollen from oil, and may only show the leak/hole under boost/pressure. Check for loose hose clamps also. Rarely, the intercooler itself is blown/leaking.

Mark