hi with all the problems you have just mentioned i would check the engine earth cable.....it goes from the battery down to the starter.....check all conections are tight and clean
the sticking throttle and choke cable are due to a bad earth and have tried to earth through the cables
this heats them up and makes them sticky
you will need some new one's
You've routed the vacuum lines wrongly and have now created a low manifold vacuum pressure. That's why the econ gauge is now reading wrong and why the engine runs like poo, doesn't idle properly etc etc etc.
Erm, your thermostat is worn out and needs replacement. Don't be stingy and try and buy cheap rubbish when a proper Volvo one from the dealer is less than 15 quid and will work properly.
If you get a cheapy one you run the risk of overcooling again which will wreck your engine because it doesn't get hot properly and overheating which will warp things and eventually seize the engine. Just my twopennurth. Some things you can save every penny on. Some things you just can't
The vacuum lines are the same as when it worked. this time however the hoses are new and the t-piece is new. the econ gauge works fine as a suck test shows, but not when the car is running.
*edit*
The lines goes from the carb point where it always has. to a t-piece for air re-circ then straight into the T-piece on the head. the air re-circ hose has the T piece for the Econ gauge, as this was the only place it would work when breather was held together with tape.
ah right, well does the hose that goes to the carb base plate have the correct restrictor in it? It needs that calibrated orifice to prevent too much air going in simulating an air leak. You might be able to get it out of your old hose and place it into the new one.
i don't think there is or was any kinda of restrictor in the pipe. if there was where would i be looking? i.e straight after carb? somewhere in middle?
Make sure you have the econ tap on the correct side of that restriction.... not that I've made that mistake and my econ didn't work can't rememebr which side it is, but i do remember posting it when someone (might well have been you) was having trouble getting that and re-circ to work