It wasn't when I first got it, but I swapped out the battery tray and strap from my silver ludewurlycorner wrote:'tis true that the O2 sensor has no part to play in engine mixture until the engine has warmed up.
Nafe, is your battery even secured down? I can't see a tie down strap in that pic? (or do that have clamps at the bottom on a 5g?)
If not, that combined with a dodgy terminal is definitely where I would start!

Going to check out the wire gauges when I get home and then order two new terminals.