Saab: 88 900 turbo not starting, dirty fuel, foot on the gas

Question
i have an 88 900 turbo with an automatic. i bought the car as a non runner for a great price and love it, but am having trouble getting it working. i took it to a mechanic and they replaced the fuel pump and got it to "run". it is very hard to start. it will fire on one cylinder only after cranking for a while then with luck on two, then on three it will start to run and eventually run on all four. the whole process takes about 4 minutes to fire it up. it will not idle, i have to keep my foot on the gas or it will die. if i shut it off, it will not restart. the mechanic believed it will clean itself out since the gas in the tank was pretty old. i think it has bigger problems. i appreciate any help you can provide. thanks a bunch

Answer
Cory:
 Your mechanic's idea of "bad gas" is a good one, although I am inclined to think its a dirty fuel system as well...likely gummed up as a result of a long period of idleness. If possible, can you drain the existing gas and put some fresh stuff in, along with some of the commonly available fuel system additives(GUMOUT, etc)? (I get the most expensive one for such problems, probably around $9. per bottle) and just let it run, run, run itself through. After that, if not 'fixed', you may consult with me as to the next step, providing your observations "along the way".