P0172 Help!

[Vella's Alero]

Ok, so after replacing my pre-cat O2 sensor, I cleared all of the codes and drove my alero (v6). Now I got another code (they never seem to stop!). This one is P0172. I know it means that the fuel air mixture is too rich (more gas than air in the mixture) and it is in bank 1 ( cylinders 1,4,2).

The only mod that I have engine wise is a CAI. What could be the first few things that I should look at? I have thought of cleaning/replacing the air filter, cleaning the MAF, and then I run out of ideas.

What else should I check?

Thanks in advance.

[comanche]

Why did you replace the O2 sensor? What code was it throwing?

Does your scan tool give live data and fuel trim numbers?

Are there any other codes?

It's fairly common to have injector problems with these engines (such as leaky injectors) but really it's just a guess without knowing more....

If your air filter was plugged I suppose that could make the car run rich.
MAF... cleaning is not recommended.
Do you have a K&N on the intake? Over-oiled?

[Vella's Alero]

I replaced the O2 sensor because it was giving me a code that it was faulty.

My OBDII doesn't give me any of those numbers. It's a very basic one just for codes really. I could get that looked at though.

There are no other codes.

The air filter is a little dirty because I have had it on there for a few months in the winter so I will eventually be cleaning or replacing it. It is not a K&N filter. It is just the one that I got with the intake and I never oiled it and dont think it came that way either.

Why is MAF cleaning not recommended?

[guiguilandry]

In case you don't know... bank 1 is cylinder 1-3-5... bank 2 is cylinder 2-4-6...

[Vella's Alero]

yeah...I kinda figured that after writing it. I had the coil pack numbers in my head.

So an update... I reset the light and it hasn't come on again but I have only traveled about 20 km so I will let you guys know if it goes on again tomorrow or not. It might just need to relearn the mixture since it's been off for so long (for the longest time I thought the code was still the evap code)

[comanche]

MAF cleaning will generally void the warranty, what the cleaner sometimes does is remove the protective coating on the wires, so the wires in the future will get gummed up faster and you might have to clean them regularly. Plus if you get any fluid inside the little module, it might end up junk.
Injector balance test might tell you if there were injector issues.
Do you ever have a running rough condition?

[Vella's Alero]

It's never running rough but just lifter tick which is common in 3400's. Other than that it has worked fine. I might have a chance this week to check a few things so please keep the suggestions coming.