Loooong time lurker here and I've searched a lot.

2 years ago fell victim of the 64K mile timing belt break.

Well the car is immaculate, (still is inside and out) so I decided to have the 1600 head job done + timing belt + everything else.

Fast forward to a month ago (now i have 94K miles). Car overheated. Leaks in heating hoses. Had all replaced and a stuck thermostat. Also Shocks and struts! Compression test was done to diagnose any outstanding head issues.

Was running like a champ for the past 3 weeks, now I have extremely rough idle and low end just ugliness. Engine light is on.

p1781, p0700, p0300 all lit up in my OBDII reader. So reading on here I replaced: Upper O2 sensor on manifold, plugs, plug wires and coil pack.

Cleared codes but same symptoms remain...and codes lit up again.

Wondering what on earth to try next... Would hate to find out I have another Head issue. Just noticed there looks to be another O2 sensor below the Cat. Should I replace that too? Would a bad Cat cause crappy idle too?

Before I dump more money into this aveo, just wondering what you guys think and what I should try next...

Thanks in advance