Serious Starting problems

I've got a manual 93 Saturn SL1. Over the past couple months the gas mileage has dropped from about 29-30 MPG to around 20. I haven't had time to look at it, because I"ve been traveling away from home ALOT. I figuared maybe an oil change and/or new plugs and wires, because I hadn't done a tune up on the car since the dealership, rebuilt the upper half of the engine over 2 years ago. However, after getting the car home, It made a few funny noises and ran rough right before I turned it off. The next morning, it will not start. The engine turns over and spits and sputters and will almost start when I push the gas to the floor and sometimes backfires, but it will not start and stay running. Any help on what may be the problem. I did push it into my garage and check the plugs, they were bad and I cleaned then. They were black and smelled of gas. When I tried to start it, I also smelled a gas smell coming from the car. Any ideas what maybe the problem. I'm going to crawl back into the car tomorrow and see if there are any problems coded popping up or such. Please help!!!. Reading some other threads, it sounds like problems others have have with the engine coolant temp sensor... Maybe???

Thanks,
Charles

a possible cloged cat i bet. remove the O2 sensor and try to start, if it starts have it towed to a shop for repair, as that little hole will not allow it to drive very well.

well the simplest and cheapest thing to do first, if not done, is to replace the cts sensor. it is a typical problem with saturns, which causes rough drivability, loss in gas mileage, and possible no starts(more of hard to start). a new replacement cts sensor will be brass, if not its junk. also get this part from the dealer, if not it will most likely cause a problem soon after installed.