Just adopted ($700) a neglected and butchered by mechanics ’99 S80 6T. I have access to a friend auto repair shop, I am handy and I have a good help: a VIDA.
So far in one week I replaced all front suspension , rewired the electronic throttle ( inexplicable had a +12 V on the ground wire) , fixed the SRS ( bad belt pretensioner ), replaced stolen speakers , patched some air leaks in the intake, bypass a circuit which still have +8 volts on it ( relay activated by ignition on ), hence 600mA current drain and the car runs decent. I still have a lot of work to do: windows regulators, fog lights, daytime running lights shunt burned in the fuse box ( replaced for now with a fuse/ does not dim but… ) sun roof, a lot.

 

Welcome. Sounds like you have a big job on your hands. But to pick up a 99 for that small amount of $$'s you can afford to put some money into it. You didn't say how many mile it has, but if it is over 70K I would definitely change the timing belt. Good luck.

 

Sounds like you have your hands full with that car. Good Luck bringing the Volvo back into running order..... I too agree with the timing belt and tensioner. Welcome to the forum!