It'd be usefull if you posted a bit more info on this car, and what you've done so far to address your problems.

I own a 1986 740 GLE that I paid $1,000 for with 163k miles on it.
It's had a few problem, but it was a very nice car. I've never had much money to put into it and when my problems started to accumulate (at 235k) there were too many to deal with. It was cheaper to buy a new one for $2,900

I'm not a volvo mechanic, but it sounds like your rings are bad, fuel injectors may be clogged, spark plugs are bad, and your gaskets are blown. Your valves might also be bad.

I'd say try taking it to a mechanic for an inspection and find out what you're up against before you decide to dump it. In your situation I'd recommend finding an older volvo, particular the old 140s - built like a tank with an absolute minimum of electronic components to go bad.