Is this true? Ive had a slight exhaust leak for about a month around my manifold.....its not a HUGE leak, as you can BARELY hear it...Just wondering if that affects the BLM's? Ive noticed since Ive heard it that the BLM's arent really in harmony with the INT like before. Guess I should just tighten up the leak and see what happens....if they weather holds out. Thanks in advance.

If its on the side with the 02 it can. With manifolds it might not be as much of a problem. With headers, though, the pulses pull alot of air in behind them

Well...Im not exactly sure what side its on...sounds like the driver's side. The car itself has manifolds on it. I noticed it about a month ago coming home from work...I was at a stoplight next to a truck..and I could hear the ticking a little....I got under the car and felt around where the down pipes connect to the manifolds...but felt no air. I recently replaced the pipes when I did the cats....I bought the Catco dual cat setup with the dual pipes. I checked the manifold bolts and all were tight.....cant figure out where its coming from...

Is it actually up by the header flange? Try tightening down the header bolts again, they tend to work loose.

I'm not sure if you bought your headers new, but I bought a set used once that had a pinhole leak or two around the collector.

Exhaust leaks will really skew o2 reading causing o2 to think car is lean therefor adding fuel.
When my driverside collector flange leaks it really messes with the 02, even though it is about 6 inches past the 02 sensor.

When I run uncapped I have to lock BLM and INT.

The O2 may get a false reading if your leak is upstream from the sensor. Downstream not a big deal.

False, read above.
I see lots of problem when my collector gaskets leak on drivers side despite being 5" past sensor.

Oh well, mines not affected much.