The MAF can NOT cause a "lean" code on a single bank. It will affect BOTH banks equally. Don't waste the time messing with the MAF if you have a single lean code.

Single MAF codes are almost always due to an air leak that affects one bank more than another. The include intake vacuum leaks, exaust leaks (upstream of the first O2 sensor), and possible injector faults.

By far, the most common reason for "lean" codes is, as already stated, intake vacuum leaks. This cannot be emphasized enough. The PCV hose elbow, common to all engines on this platform, share this common failure item.

The inexpensive code readers cannot read PIDs or present freeze frame data. Those scan tools are in the $200-300 range typically (ie, Actron 0145 or 9150 or comparable). I use an old laptop with OBD-II interface that does do all this ($120s from Alex Peper).


Steve