Help! Po171,po174 Lean Codes

**SSTODD** · 05-25-2007, 05:36 AM

I had this pop up the other day while driving, 85+ degrees out and I did have the air on for awhile but it was off when it happened. I had it cleared and it has not come right back yet. I had this pop up once last year also and cleared it. What do you guys think? Is it the maf, Be gentle with me

2000 SS A4 18,000 miles
lid, bellows, slp maf, ngk plugs, msd wires, free mods, S3 T.B., slp cat-back, kn air filter.

**bevenue** · 05-25-2007, 06:21 AM

Mine had those codes before. It was a hole in the PCV line next to the intake.

**SSTODD** · 05-25-2007, 09:31 AM

Any other ideas out there.

**stanger88** · 05-25-2007, 10:56 AM

**JonD99** · 05-25-2007, 12:10 PM

That code popped up a few times in my Z too. But last year i got o2 sims and swapped out my front o2's and i haven't thrown that code since, FWIW.

**slims00ls1z28** · 05-25-2007, 12:20 PM

Bad O2 sensors can shoot those codes as well as bad cats.

**2001NBMZ28** · 05-25-2007, 12:34 PM

www.gearchatter.com/viewtopic9039.php Wouldn't worry about it unless they keep coming back.

**stanger88** · 05-25-2007, 01:51 PM

Originally Posted by slims00ls1z28

Bad O2 sensors can shoot those codes as well as bad cats.

So can exhaust leaks right before an O2, as was my case.

**SSTODD** · 05-29-2007, 02:47 AM

Thanks everyone, I swapped my stock maf in and took the slp out. I am going to see if I see any more codes. I wish I had read all the threads on not buying a maf over a year ago when I did buy it.