Tough one: engine runs rich - O2 says lean

[Ferret]

Is the exhaust leak before or after the o2 sensor?

If it's before, it's dragging fresh air in and screwing with the reading - just making it overfuel even worse.

[Anton CH.]

Is the exhaust leak before or after the o2 sensor?

If it's before, it's dragging fresh air in and screwing with the reading - just making it overfuel even worse.

Exhaust leak doesn't necessarily have to be upstream of oxygen sensor. Just in near proximity.

[Ferret]

Exhaust leak doesn't necessarily have to be upstream of oxygen sensor. Just in near proximity.

If it's downstream of it, it'd have to be very close to the sensor, as I dont think fresh air could easily backflow up an exhaust, even at idle?

[Bruno]

Exhaust leak doesn't necessarily have to be upstream of oxygen sensor. Just in near proximity.

Ok, there is a leak near the O2 for sure, I can feel it... that should be a starting point. I will try to locate it then JB weld or go back to the muffler shop and have them work their magic.

Thanks that is a start.