Volvo Repair: Poor take off, boat anchors, dirty fuel

Question
Hi
I bought a 1984 Volvo 760GLE V6 about 2 weeks ago. I bought it with a bad idle got it checked out turned out to be High tention lead so had it replaced, from that point it ran a lot better then it did before, the continuing problem is it has a very slow take off from stand still, backfires slightly and tends to have a very slight pulsating run at different speeds kind of like if you tap on the exelerator, now my mechanic said it had a dirty fuel system when I had the tention lead replaced so he added a injector cleaner in the fuel with not a great deal of effect, when I asked if it could run better he suggested a new engine but surely it could not be that dire could it?

* I run the car on volvo suggested BP Ultimate

Please help.
Thanks

Answer
Corey, those old V'6's sucked when they were new.  It could be the fuel distributor.  Im assuming it a CI fuel system and not EFI.  It could be anything from bad wires to Spark plugs.  Very temperatmental engines they were.  Putting a 4 cylinder Turbo motor would be a better option than trying to get that thing right.  We call those engines Boat Anchors.  Roger