Hi, i'm new here ok, ASE master tech but still learning a lot. i'm working on a project car 2010 S hatchback. it sat for around 2 or 3 years. i just got it up and running, but it's running really bad. stalls out a lot at idle and slow speeds. i'm working on that. i left it parked for a week with a battery that was new but returned as defective to my shop. i charged it up for a while and it tested good. i replaced the in tank low pressure fuel pump because the old one was shot. after replacing, the vehicle had a lot of trouble starting the first time. took about 10 tries of cranking for it to fire. couple days later drove it like 80 miles round trip for some stuff. it would stall out at idle. some times took 3 or 4 times cranking to get it to fire back up. the battery had no trouble with cranking multiple times and would always crank it fast, car just struggled to start. i parked it somewhere and it sat for a week and it's been really cold this week (40°f at night) i don't have the keyblade. and my FOB is just the transponder, no guts for lock/unlock doors so i had to leave it unlocked. it seems the battery died. today my partner went to pick it up ( i cannot go to the place the car is now, i am restricted from going there). he said it wouldn't crank. tried jump starting it, wouldn't crank. with the jump car hooked up the lights and all came one but no crank, just a click. i have heard that it's possibly could cause some problem with immobilizer because the battery died? obviously the battery was dead when it sat so long so i don't know. anyways i got a new battery that my partner will install in it (i will teach him how to replace by showing him on my other mini) and hopefully it will start but is there something obvious i'm missing? thanks