my car will crank but wont start

How long did it sit ? Could be bad gas , purge the line if you can , get most of it out and try an octane booster . There's different formulas for winter gas and summer gas .

It sat for a few months we had a mechanic work on it and he switched the ignition coils and mismatched them and it wouldn’t run right so we let it sit after a few months we needed to move so we had a friend of ours look at my car and he figured the ignition coils were in the wrong spots so he put them in the right order and it started right up we filled it with gas and let it run for a little bit Bc it was sitting so after idk if it ran out of gas or what but after it would want to crank but not want to start and the battery was old also we had to jump the battery for the car to start it wouldn’t so it sat for a few more months and I went to go check on it and there was this like white foamy substance on the battery and the terminals