Help me Please.....

I've got a 95 Taurus. Here's the problem. When cranking, sometimes it turns and then runs so low it cuts off. Example: I crank it. It's having a hard time turning so I give it gas. It turns after 4 seconds or so but as soon as it turns, it is idling very low and it cuts right off. Now if I quickly throw it in reverse or drive, everthing is normal. I have no clue!!! Can you guys give me some things it could be. I've come up with starter, alternator, fuel pump, tune-up. I dont know much about cars but this is killing me. The car has 115,000 miles on it. The bad thing is that once it's started, its fine. Even if i turn it off. It only happens when it's been off for a while like overnight or so. It sounds like it could just need a tune-up. I hope so. Last time, something like this happened to my Mazda and after over 1000 dollars later, I had a new computer chip or something I had to put in it. It got to the point where it would never start. help me out guys.

could be plugs, engine coolant temp sensor,i'm not to sure. have a diagnostic done so it ill be fixed the first time

I checked with my Haynes automobile repair manual and it said it could be a fuel-injection problem, a distributor rotor is carbon tracked or damaged, or your battery is low. My guess is to try a tune-up. Your car will not suffer and it is something you can do without much expense.
Also, if there is a code error, take it to a local auto parts store to have the codes checked for free! Good luck.