CEL P0174

[Passport1]

Sitrep;

2006 Suzuki Grand Vitara 2.7 V6 155K miles

P0174 code. Lean bank 2

Previous action, once @~105K, replaced upstream O2 sensor with OEM Denso unit. Problem fixed.
CEL 5 months ago same code, added a bottle of Techron and cleaned MAF sensor with proper MAF cleaner. Problem fixed.
2K later same code. Added another bottle of Techron, will clean MAF sensor again.

Can't find any obvious vacuum leaks
Vehicle runs fine, no idle problem or stalling. Good power. Always a thirsty engine so never accurately measured mpg but still probably about 20/21. Vehicle is primarily driven around town. Unlikely to be weak fuel pump. Uses a small bit of oil, no leaks.

Suggestions?

 

[Kira]

20 year old vehicle poopin' around town...replaced one upstream sensor (there'd be 2, yes?) 6 years or so ago...
How many downstream sensors are there?
Every O2 sensor might be bad.

 

[JTK]

What do the long and short term fuel trims look like for each bank?

 

[GMBoy]

You have to smoke test with that code to be 100% sure there are no leaks. Trust me you will find them with a smoke test not just looking around.

With that, you mention you cleaned the MAF. That usually works but if it comes back, which it did, means you have to test that MAF and probably replace it if a smoke test shows no leaks. Check fuel injector balance as well.

If you want to guess and throw parts at it - my money is on the MAF sensor.

 

[GSCJR]

First, test the downstream oxygen sensor @Passport1

 

[iCurious]

Need scan data to be helpful.

 

[Marcozi]

For data collection use the OBD2 app.