Very rough Idle, check engine light, random loud clunking sound......

[WitiTune]

Changed the Tensioner Pulley today.. Car still runs rough.

Will pick up an 02 sensor in the morning. Should I be replacing both sensors (as in front and back). Could only get the front in-store so I'll change that tomorrow. Hoping that makes a difference. I have all the symptoms of a failing 02 sensor, apart from blowing black smoke. Car hasn't done that, yet.

I wouldnt just go and buy 02 sensors on a whim. If you are somewhat mechanical I would remove the cats and do a visual inspection before doing anything else. Alternativly use and obd reader and see what the voltage readings for the 02 sensors are first.