Ive had my GX for 4 years or so, its always been spot on but, the last week or so its been getting really hesitant to pick up, running rough and finally tonight it actually back fired and lost power, I had to change to bank sensor earlier in the year but apart from that the cars been faultless, any clues as to what the problem is please

 

Best bet you are need diagnostic,if someone in your area have OBD reader,check codes.
I'm not sure,but maybe will be 02 sensor or MAF,but without the diagnostic is just guessing.

Jura

 

I have no OBD light showing, would that always show ?