Car wont boost under load...Doing my fcuking head in! Can this be due to a bad alternator? I charged battery took it for a drive, drives ok for like 5 min then as soon as you try and load the car up it dies/backfires/ and just wont run. nurse it home and switch it off, leave it for a bit and battery is flat. So is this issue due to bad alternator? Ready to scrap the dam thing I'm that over it.