P0171, recurring, never a P0174. Cleared multiple times, doesn't seem to recur after any particular thing. Longest it went away was about 700mi. Came back on just cruising on the freeway. Another time, came back on just idling. It seems the majority of the time is freeway cruising, but not always.

Mechanic says vac lines look OK, didn't hear signs of vac leak. MAF has been cleaned a few times w/ CRC MAF Cleaner.

-What are some other troubleshooting ideas, other than a new MAF, that I could try?
-Why would I get only a bank 1 code? It seems like if it were something like a MAF then both banks would be affected, no?

 

several things i would look at, are exhaust leak, 02's, intake, intercooler, gaskets, pipeing and hose connections. I watch the short term fuel trims on a scanner while spraying connections and ports, if it picks up the spray you'll immediatly see it on the scanner. listening and even spraying for rough idle will never be as telling as short term fuel trim. Next, or first, do a hard reboot of the ecu with the battery(neg disc. and touched to positive) this erases long term fuel trims values that will NEVER be corrected after a repair before it sets a check engine light again. I cant count how many times ive watches techs chase a problem that was no longer there after a repair cause the long term fuel trim was still corrcting a problem that was fixed creating another problem.
and yes the mass air flow can, dont ask me why cause a single bank to run differently, but barring a deteriorated intake tube, this is the #1 cause of lean or rich codes on that car

 

Is there a way to check if the MAF is bad? Like, a certain voltage reading it should have that I could test? I have a person I can buy a used MAF from for $120, but I don't have the scanner equipment to know if it's truly the problem. My mechanic seems to think it is, but he hasn't run any true tests. I need to get a hold of him tomorrow i guess and see about running a real diagnostic.

 

well you need to see datastreams and look at grams/min from the mafs, looking for erroneous readings, or dropouts. But for us at a dealer, we believe its the problem and put 1 in and if not we take it back off. This is another benefit of dealership work, otherwise you bought it. But i can tell you that if you brought it too me, this is what I would say would fix it, no diag needed..... well at least after a few fast looks at the things I mentioned