Did you ever find a solution to this I have the exact same problem sounds like a golf ball doing a long roll on acceleration and rolls back on breaking. Sounds like it is under the center console.

Spark plug distributor / diagram

Just wanted to clear this up for all 850 models. It does work but some of the instructions are brief. Here is a step by step for programming up to 3 remotes. 1) Close all doors and gate 2) get in car 3) lock all car using the door button on the left of the driver doors (not a keyless) 4) place key i...

I heard the same about a new key but I just went to a Volcvo dealership for a replacement (850 1994) key and they gave me two keys for $50 total! Both work.

wynnevolvo.com in Hampton Va was the place. Not sure what he did but he said I needed to have the car with me.