Why won't my car start?

So here's the deal: my friend's car (a 1997, Saab 900, not turbo) is not starting. He has had a great deal of car trouble lately and had to replace his battery just last month. So we know that it is not his battery that is giving us trouble. When he turns the key in the ignition the car sounds as if it is starting and even rumbles as if it's just about there, and then doesn't go any farther. It seems to be coinciding with these cold weather spurts that we've been having up here in Maine as that tends to happen in the winter. Another instance that may occur when he attempts to start his car is that it does start but then turns itself off after a second or two. I was looking online at the alternator but it doesn't seem like that is it. I was also wondering if it could be a spark plug or something of that nature. Either way, I would love to hear some ideas from those experienced with cars before he spends the money to take it to a mechanic to get some information that I'm sure I could find online. So anything is appreciated! Thanks!



(He has also tried adding dry fuel to his gas tank which did not work and another thing that's name has slipped my mind at the moment. It's that fluid that you add to the gas tank when it's full and it prevents hard starts. And would you believe it, it didn't work!)Why won't my car start?
well you have to go to the mechanic and find out, that could be several things, probably is your fuel pump and filter that your friend should get replaced.
Could be a fuel pump issue. Fuel not reaching the engine. If it has not had a tune up in a while, it would not hurt it to get one.Why won't my car start?
unplug the map sensor if it starts get a new one if not plug it back in and try the fuel pressure
Ok here goes some possibilities:

It could be your starter or flywheel, but that might not be it because you said it sounds like it wants to start. Fuel pump or injector; not sending fuel to the engine; fuel might also be frozen in the pipes. Spark plug might be off timing; get a tune up to fix it. Alternator might be draining your battery.Why won't my car start?
i would suggest putting HEET in it but that is probably what your talking about when you say the fluid that prevents hard starts but i would also try putting starting fluid in the carb. it isn't the spark plug because if its starting up then quitting it is producing the spark but the cold air is harder to expand then hot air the way to see if it is the spark plug is take the plug out with a plug wrench usually a 5/8 then put the spark plug on the head and have whoever has better vision watch the spark plug to see if it produces spark. make sure you put the threads on the head, don't worry it wont be much spark so again watch carefully but most likely the car doesn't have too much power and the cold air is hard to expand but that's what the starting fluid is for
Oil too heavy, Try 5W-20.