exhaust leak that might cause lean o2 code?

[jeff89fbird]

Hello, decided I'd try out this site too. Been on 3rdgen for awhile. Anyway, here's my problem.

I've been getting a code 13 (lean o2) and the car's running rich. I just found a huge exhaust leak halfway between the o2 and cat. It's where my new pacesetter pipe inserts into the old pipe. It's leaking at least halfway around the pipe. Would that somehow cause the lean o2 reading?

I've heard on 3rdgen that a leak around the o2 would cause that, and I'm trying to find out if that's close enough. (Beside ovbious back-pressure issues)

I'm also losing fuel pressure, and it's either going back into the tank or leaking through the injectors or cold-start injector.

It's running super-rich. plugs are all black, sucks down fuel, etc.

The injectors came with the 3.4 I got from the junkyard. The engine has been rebuilt, but the injectors weren't.

edit* went out looking again and found a header gasket leak on the right center tube. I'll try to get in there and re-torque those tomorrow.

[corning_d3]

A crack near the O2 could cause a lean reading, since oxygen-rich air is being pulled into the exhaust. The engine, thinking it's running too lean, is dumping massive amounts of fuel to compensate. This is hard on an engine since running rich tends to wash oil off the cylinder walls..