The mileage on these plugs is unknown, as this is a used vehicle w/o a complete service record. All 3 plugs on the driver side (4,5,6) were almost completely eroded. The 3 on the passenger side (1,2,3) however, showed very little sign of wear. Is the driver side fuel/air mixture more lean than the passenger side, thus making it burn more hotly? Is it even possible for one half the engine to get a different fuel/air ratio than the other?
[![enter image description here](https://i.stack.imgur.com/czRw5.jpg)](https://i.stack.imgur.com/czRw5.jpg)
[![enter image description here](https://i.stack.imgur.com/328M2.jpg)](https://i.stack.imgur.com/328M2.jpg)