Will a vacuum leak on the AOS affect the right bank more?

[Dale_K]

I got the 1126 CEL this week and I'm thinking about the repair strategy. Correct me if I'm wrong but the 1126 code is saying the right side cylinders are running lean. Seems to me there are two basic possibilites:

1 - The control system (MAF sensor & O2 sensor) is working correctly and I have a vacuum leak.

2 - There is no vacuum leak and I have a bad sensor.

The AOS seems to be a common vacuum leak failure point but I don't understand why I only get a code on one bank. Does a leaking AOS bellows tend to make the right side go lean or both banks equally?

I pulled the MAF sensor and sprayed it with some sensor cleaner but I didn't see anything obviously dirty so I doubt that's it, especially with the code on only one bank. The car runs OK so far, although it briefly ran weak at low speeds after I reset the codes. The CEL hasn't come back on yet but I doubt that will last.

Also critique this repair stategy...

Buy a propane torch and try to find a vacuum leak, especially at the AOS bellows. If I find a leak that's no doubt the problem.

If I can't find a leak replace the single pre-cat O2 sensor on the right side.

If that doesn't work replace the AOS on general principles because maybe it's leaking even though I couldn't find it. I'd do this first except for the fact I'm only getting the code for one bank and I would expect a vacuum leak to affect both sides.