P0171 - System Too Lean - Bank 1

Hi everyone,

Name's David from the land down under.

I've recently purchased a used Holden Cruze 2012 SRi-V JH Series II, 1.4L turbo petrol.

I had a check engine light come on, but after some driving, it went away.

Day or two later, it came on again and now it's permanently on whilst I drive.
I had also refueled with Unleaded 95 (manual says to use 91 but 95 also worked for a little extra performance), not sure if the light returned after or before I used the 95, but recently received my OBDII reader and that's how I got the code above.

I noticed the STFT would be around the -3% to +4% when idling, but LTFT would be around +30%.
When accelerating and driving/cruising, they'll both float around the -5% to +5%, sometimes going up to +10% depending on when I'm accelerating or decelerating heavily, or something, too random for my basic knowledge to pinpoint.

I do notice when I come almost to a stop, STFT jumps to around +15% then drops back down again once I've stopped, or start accelerating again.

I did some basic troubleshooting, tried the water spray method but I think it was too windy or something.
Anyways, tried the purge valve and when the car's on idling, there's suction, so I believe that's one problem.

But based on the above STFT and LTFT details, could there be anything else?

Thanks