You might have an idler pulley or tensioner pulley going bad on the timing belt, or it's the water pump bushing going bad. If any of these are happening, they can take out your timing belt, so do not drive the car! A broken timing belt will cost you $4k in bent valve repair. Have the car towed to your mechanic. If you aren't sure of maintenance history, have everything replaced, belt, pulleys and tensioner.

My Volvo indy told me a story of an 850 that he backed out of the garage and left it idling while he closed the garage door. Timing belt broke, bent all the valves--just sitting there idling...
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96 850T, Bilstein HD, IPD swaybars