I have been having starting issues with my 2000 s500 since a few days ago in the morning. It would crank for 5-6 seconds , worried it would burnout the starter i would stop it . I attempted cranking several times with no luck. Also checked for blown fuses hoping it would be an obvious problem. After 20 minutes of not finding nothing decided to try starting it one last time. Car started and worked fine for that whole day. Next morning same thing but this time it didnt turn over at all. I took battery out n got it tested apparently it was bad. Got a reconstructed h8 AGM battery installed it and it cranks now but wont start . Upon taking the cap at the end of fuel rail and turning key to first position fuel spits out, so i know fuel is getting to injectors. I threw a bit of gas through carburetor and it starts but as soon as it burns it shuts off. I tried to accelerate a bit to keep it on but it still shuts off.Im stumped to what could be the cause?