Ok, for some reason, Volvo likes to overengineer things and the PCV system is one of those things. Now, what you'll want to do is look down at the fresh air intake pipe right before the turbo. You should see something like what is in this diagram. Now, unplug all of those lines and check for clogging and clean as necessary. Sometimes, those lines are all that get clogged and you get off easy by only having to clean them out. Usually though, the problem lies deeper. So, what you'll have to do is pull the intake manifold. You have a '95 model, which does have EGR, and makes the job a big pain in the neck. Now, what you'll want to start with is unhooking the intercooler hose that goes to the throttle body and you'll also want to loosen the bracket that holds the hard IC piping over the engine. Then there are several other hoses that must be detached from the intake manifold up front on the driver's side. One of them is the evap valve hose and one is the CBV hose. You'll then want to detach the hose from the Idle Air Control Valve, the silver cylindrical thing up near the manifold. That should cover all hoses that need to be removed. Next, you'll want to unbolt the dipstick tube from the manifold. This one is tough to get to b/c you have to do it from underneath the car using a combination of long ratchet reaches to access it. I believe it's a 12 mm bolt. You can then just rest the dipstick tube against the fan shroud once loose. Now back up top, you need to unhook the throttle linkage from the throttle pulley bracket using needle nose pliers. I forgot to mention, you have to take off the plastic throttle cover, which is held in by a torx screw (T25 I believe) to get to the throttle area. Alright, now you'll want to remove the throttle body, which is held in by four 10 mm bolts. If you're careful, you can re-use the TB (Throttle body) gasket that is already on there. Set the TB on the side. Then, you'll have to undo the EGR bolts. There are two 8 mm bolts holding the EGR diaphragm to the intake manifold. I will warn you now that accessing these things is a big headache, but it can be done. Once unbolted, the rest of the EGR assembly will just sit in the engine bay. Now, to take the intake manifold off: I believe there are seven 10 mm bolts actually holding the manifold into the head. There is also a bracket down below that is tough to see that has to be unbolted as well. You can re-use the manifold gasket if you want. Once pulled, you'll see a squarish black box on the passenger side (the rectangular black plastic thing on the driver's side is the starter). That box is the oil trap and is usually what gets clogged. It is usually replaced with a new part, which costs about $30 at the dealer. You'll want to remove all hoses going to it and verify that they're clear by blowing through them. Here is a complete diagram of the PCV system and it's parts. It would also be a good idea to clean up the knock sensor connections while you have the manifold pulled. They're the two little black things with electrical plug-ins. Re-assembly is opposite of disassembly.

Good question. You will need to move the fuel rail out of the way. To do this, you'll want to first remove the bracket that holds the lines to the block. Just follow the lines back and you'll find it. Then you'll need to remove the two 10 mm bolts holding the rail to the manifold. I should note that before you go any further, the negative terminal of the battery should be removed and nowhere near the post. Sparks could cause BIG problems. Then disconnect the electrical connections from each of the fuel injectors. You can then pull upward w/ some force and the rail and injectors should come loose. A bit of fuel will come out; don't be alarmed. There is only a small amount and it can be wiped up with a shop rag. Be careful not to lose any of the injector o-rings. I'd suggest setting the injectors aside until it's time for re-assembly simply for the sake of cleanliness. You can wrap the rail in a towel (for cleanliness) and rest it on top of the spark plug cover. Be careful when replacing the injectors back in the rail and the rail back into the manifold as the plastic around the needle is brittle. Also, FYI, the rail can be removed in place w/ the manifold, but I wouldn't recommend it b/c the soft hoses connecting the hard fuel pipes is very brittle and often cracking on many 850's that I've seen.