1993 Toyota Camry My 1993 Camry Runs Rough, Stalls and I ha

Hello, My name is Dave and I currently own a 1993 Toyota Camry LE 2.2 4 Cyl with about 117,500K Miles.I bought the vehicle in July of 2009. When I firsh purshased the car it seemed fine but about a month after buying the vehicle and Started getting a very Rough Idle while at stop's. Somtimes my Rpms would Fluctuate and eventually stall and I would have to Start back up. About a month and half later the Timing Belt went in the car and I got it Fixed by the Repair shop I bought the vehicle from. Also got a Water pump. This repair did not make a diffrence with the Rough Idle and Stalling.I Installed New Spark Plugs, Ignition Wires, Dist. Cap w/ Rotor.I Did a Throttle Body Cleaning thinking it was the IAC Valve(I Even bought a Used Throttle body with the IAC Attatched and Throttle Sencor and I Istalled it and Still had the Same problem).I Live in PA and its very cold expessially since I work overnight its in the 20's when I leave for work and I somtimes have trouble starting my Car. It will keep trying to crank and it just wont start. This is what's really getting to me. So I took back to the shop and they Installed a New Fuel Filter which did nothing.I then Put a New Battery in and Also Put in a New Air Filter. Still having the same problems.A couple weeks ago I was driving at High Speeds over 55 and Right after I got over a Hill and Stopped to Turn My cars RPM'S started Fluctuating and I started Smelling these burnt Fumes, So I let it sit for a Couple mins and started it Right back up.I really need help. Ive looked at other forums saying it Could be the EGR, Coolant Temp Valve, Maybe the Cat.(Also I Smell Gas Somtimes to when I start my Car). Please give me some advice what you think it might be. Thanks so much.