A Ticking I just purchased a 1995 Volvo 960 4 door sedan for a steal. The care had been sitting for two years. I went over yesterday and started the engine (jumped it) to let it run for a bit and could hear this ticking noise under the hood. Realizing that the car has been sitting for two years,do you think it could be something serious?

take a lead from your battery .then reach under the inlet manifold. remove the 10mm bolt and copper washers one each side of that bolt. that is the feed line from your fuel rail to the cold start injector .now remove each of the ten mil bolts holding on your fuel rail . now remove the clips holding the injectors to your fuel rail. place some clothes under the fuel rail and lift off . care needed due to fuel wear eye protection due to fuel pressure..

is the cooling fan on all the time??

The O2 sensor is located beneath the cabin, on the exhaust line, immediately in front of the catalytic converter. You must go under the car to gain access to it.

A shaking engine usually is an indicator of an engine missfire. Secondary ignition components are the most common failure (Spark plugs, plug wires, etc..). Less likely, but still a consideration are the fuel system components such as the fuel injectors or filter. Further down the list with a vibration in gear at idle are bad engine mounts. If it worsens with engine load such as acceleration then it is likely the ignition system.
Good luck

usually its the sway bar links that rattle horribly,it sounds like the suspension is falling out...but its not, the sway bar links are usually pretty cheap and not bad too replace,if you can get under the car grab them and give em a good pull ans u will usually feel a little play in the ball and sockets on the ends of them,hope this helps,or have your hand on one and have a friend rock the car side to side and u might feel it then

check fuel pump and fuse and relay+change fuel filter.

the firsrst thing to check is a FUEL-VAPOR LOCK and evap system esp[ecially the fuel cap and running the A/C can cause relays to get hot and check fuel pump relay and filther and last fuel pressure

try junkyarddog.com or a salvage yard near you and you can try jcwhitney.com and for diagrams pictures and step by step instructions try autozone.com or your local library

It's an inline-6, not V-6.
I'd think you could just drop in a 95' i-6 and use the 95' ecu.

Though, I was unaware that there are any changes.. it should have 60-2 on both, as well as camsynch.