Ok.....where to start

Had classes at Ivy Tech and everymorning while sitting on a slight incline car would not want to start and would start after cranking 4 or 5 times. While on the way home from those classes the timing would retard and i would recieve code 43. Have been chasing this problem for about a month now..

Well for the past week I have been noticing a slight sumbling and miss at a constant speed with no light. I immediately replaced the fuel filter not knowing how long it had been. Problems didnt clear up.

Tonight on my way to work car was stumbling and missing every 5 seconds no matter what speed...right when i was pulling up to work...timing retarded and SES light...checked it out and the same code 43. Turned it off back on..no light or retard. After work it started up on the first crank and I had a co-worker follow me home. Turned the corner out of work going up a slight incline and the car just stumbled then died. Died 6 times going 2 miles to my house. Even going up my driveway.When I gave the car too little gas it would just stumble and then die...while giving it too much gas i would hear a popping and backfiring out of the intake and then die and no SES lights at all on the way home.

I really dont know if this is two different problems or if they are related..any help would be appreciated