I have a question for anyone who cares to venture a guess.

After passing a car (from say 70 mph-->85 mph) in my 1998 C70 and returning to normal speed (70 mph), I hear/feel 3 to 5 hollow noises-one right after the other-it feels as if, and I've never been in a car which backfired, the car is backfiring. It's a lagging type of feeling like the engine is catching up or a belt is slipping. It's such a slight feeling/noise that it's usually undetectable to my passengers. It also happens when accelerating up to say 40 mph and coming to a stop (not quick stop). I realize the 5-cyl. engine does not behave like any other, but is this normal behavior for my engine?

Also, when I start the car, I notice a high pitched noise which sounds like an engaged turbocharger, though I am not moving. If anyone needs more information to answer the question, I'll be glad to give it.

Thank you,
Mike

The whining noise on startup is your air pump, part of the emissions system. It cycles on more frequently in cooler weather.

The symptoms you describe on decelerating sound like a timing problem, don't they? You don't mention how many miles on your car, but if it's 70k or over, I'd urge you to get the car to a dealer or qualified indy tech and get the timing belt changed. It's possible, I suppose, the transmission could be cranky...an oft-cited issue on this board. I, too, occasionally feel a hiccup which seems to be associated with the transmission. One of the most frequent admonitions on this board is to *completely flush* and refill the transmission with fresh synthetic periodically.

Mrsha's suggestion to check all turbo air lines is very good advice. Inspect for softness and cracking. Typically, if there's a problem with the turbo, you feel the problems on acceleration. You probably wouldn't get to 85mph with a compromised turbocharging system.

The turbos in this generation Volvo are quite reliable. I suspect your problem is elsewhere. Good luck. Let us know how this turns out.
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(98 S70 T5SE misc mods, mostly lighting) (92 940GLE)

that turbo sounding noise i think is the air recirculater thing making hot air from turbo into the intake again

Check your turbo line air main hose .. Most I will said it came lose or not tight this happend to many turbo .. after tighting the hose the problem should go away...


1994 850 turbo 120000