Starting Problems- please help!!!

Ok I have a bit of a problem. I drive an '85 firebird LE 500 2.8 V6. Yesterday i was driving home on the highway when my car suddenly shut down so i pulled on the off ramp and onto the side of the service road where i attempted to start my car, which after several tries didn't work. The engine would turn over and start, but then would cut off immediatly. After i finally got my car home (with the help of my friend's flatbed) i checked that there was fuel delivery and i replaced the fuel filter and the fuel relay switch and made sure that the fuel pump was working. However, none of these things helped at all because it is still doing the same exact thing!!! When i first got the car (about a year ago) So i was wondering what the next logical step would be aside from going to my mechanic. Thanks for your help!

whoops i meant to put when i got the car a year ago i replaced the spark plugs, wires, and the dist. cap. my bad.

Make sure your belts are good (they're needed to keep the car running), check that the battery is putting out the correct voltage. Did you try jumpstarting it to see if it would keep running? Other than that it gets kinda serious and not worth fixing I believe. Here's all the possibilities off the top of my head:

- Belts bad, not driving the crank pulley enough to keep it running.

- Fuel delievery obstructed somehow (injectors, pump, filter, leak).

- Not enough spark (maybe your plugs got fouled somehow).

- MAF sensor (if it has one) is bad, which would stall out the car. I think this one is common.

- TPS (Throttle position sensor) is bad. (once again if it has one)

- Idle speed incorrectly set too low.

- Timing belt/chain is bad/broken. Timing needs to be adjusted.

That's all I can think of right now, the only reason I said if it has one for a couple of those is because I don't know the 2.8L, only the 5.7L but they use the same manual and i've serviced all those things above. How many miles are on the car, maybe I can give a better guess as to which it might be.

When it did start, was there smoke? If so, how much and what color? Did the chech engine light come on? Since you were driving and it just shut off, I would go through all the sensors and test them, especially the crank sensor, or have someone use a scan tool to let you know what codes are being thrown. It sounds like a sensor of some sort decided to die and now the trick is finding which one without just throwing a bunch of uneeded parts at it.

The same thing happened to me a while back. I was driving home and all of a sudden all my electronics inside started cutting off (such as the lights on the dash and stuff) and my battery started to slowly drain as well. Luckily I was right around the block from my house though. Got it home, and the next day I took out the alternator and went to Advance Discount Auto Parts and swapped mine out for a new one. Cost about $100 or somewhere around there. So make sure your alternator is fine and everything, not saying that it is the problem, but your situation just sounded similiar to the one I was in. Good luck though.