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I went out of country for 20 days and I took out my battery before i left. I've been getting this check light, but i dont know what it signals me to check, but i usually wait 10 seconds and the light switches off and i could start the car. I came back today at 3am and put it back it and after a few tries to firing it after the check light went away and it started. i drove it around a little bit to see if it was working properly and then all of a sudden it died and i was rolling in drive with the car off. So i put it in neutral and pushed it back to my driveway. then at 2pm the same day, i went to autozone and got a new battery. I put it in and the car won't start. I get the usual cranking sound and it cranks to infinity but doesnt start. I thought it was the gas for sitting for almost 3 weeks, so i went and got 2 gallons and poured it in. Still it does not start. I've been getting this check light, but i dont know what it signals me to check, but i usually wait 10 seconds and the light switches off and i could start the car. Any suggestions on what it could be?