My car is a 1997 850 GLT (2.4l light pressure turbo) with about 85,000 miles, which I bought used in April, 2000. Since early this spring, 2001 (about 77,000 miles), there has been a persistant problem that my mechanic (works for a good garage and used to work at the local Volvo dealer) can't seem to diagnose, even after talking with his old buddies at the  dealer--so he's charged me nothing while looking, but the problem still remains. Here's what happens: I'll accelerate hard (engine under load) and at around 4,000 or 5,000 rpm,  power cuts out suddenly, perhaps no fuel, then the engine will catch and fire up again after revs fall to around 3,000. Other than this, it runs flawlessly. Going back in time: Shortly  after the first time this happened, the engine ran very badly and the car was found to need a new O2 (Lambda) sensor. That was replaced (along with plugs, rotor) and all has been  fine since with smooth running in general, but the cut out still occurs. Not long before the first occurance of my problem, the check engine light came on and the codes were all  related to emissions (448, 442, 446 for air pump and air injector code). I've not had the emissions malfunction fixed because mechanic insists this is not my problem and he  doesn't want to suggest I spend $700 to shut off the check engine light. Once we did try an experiment to see if I could make the car malfunction before the check engine light came  back on with the air pump codes. I was, indeed able to make the cut-out happen with no alarm on the dash. Also, I recently had the fuel filter changed, which didn't help this  problem. Any ideas? Transmission? computer? fuel injection?
 --
 Peter Stenoien

 Make sure your waste gate rod has not been turned out, have the turbo set up by the book and see if your problem is solved.
 --
 Rich K.