P0172 and p0175

[Bhath1]

I have a 2010 Tahoe 5.3 flex fuel and I have no idea why these codes keep coming back or where to go from here. I have a new air filter cleaned maf sensor removed and cleaned throttle body replaced plugs and wires still comes back. Sometimes after 10 miles of driving and sometimes it can be up to 300 miles of driving that the light comes back. I don’t have a fancy computer unfortunately just a generic code reader. Any input would be great! It also started to what feels like misfire this morning in the Dunkin drive thru

 

[OR VietVet]

Welcome to the forum from Oregon.

Rich fuel mixtures reported at bank 1 and bank 2. Numerous components to consider for the vault. If the codes came at the same time, it is hard to believe that oxygen sensors went bad at the same time. I would first expect a vacuum leak somewhere. May also have leaking fuel injector(s).

You did not say. Codes at same time or miles/time apart?

 

[Bhath1]

The codes come at the same time. I will check for vacuum leaks tonight. Any common ones to look for that you know of? I ran a good fuel injector cleaner threw it not that I think any of that stuff actually works but didn’t seem to help. Thanks for the help

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

 

[OR VietVet]

The cleaner does not stop leaking fuel injectors. I like to search for vacuum leaks with a mechanic's stethoscope that has a hollow tube attached to hose and a rubber cone cup on the end to listen around the entire engine. I would also make sure the snorkel tube is attached tightly at all connections at the throttle body and all the way back to the air filter housing. Also look for any holes/splits/leaks in that tubing. Inspect for cracks in any hosing that handles a vacuum. Especially the pcv hose at back of driver's side valve cover.

 

[Bhath1]

thank you I will check over everything tonight after. I believe my boss has one of those I can borrow.

 

[OR VietVet]

thank you I will check over everything tonight after. I believe my boss has one of those I can borrow.

It is a very inexpensive tool for your collection:

https://www.amazon.com/OTC-4491-Mechanics-Stethoscope/dp/B000F5HUOY/ref=sr_1_1_sspa?crid=2QXIXAOFEPDEQ&keywords=mechanic%27s+stethoscope&qid=1701364979&sprefix=mechanic%27s+stethoscope%2Caps%2C164&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

They are also great for pinpointing problems with the front and rear parking sensors on the newer rigs.

 

[Bhath1]

I checked over all vacuum lines last and everything looked to be in good shape didn’t see any holes cracks etc and

 

[strutaeng]

Rich in both banks? Could be leaking injector on both banks (not too likely.) Or misreporting O2 sensors.

I don't know if those vehicles have a way to reset the alcohol content? Could be as simple as that.

Wouldn't hurt to check for fuel pressure. Maybe for some reason the fuel pressure is too high? I can't think of a case causing this.

Is the engine, install and injectors original? My 99 Silverado has these two codes, but that's because I'm running a stock LM7 tune on the swapped L59 I dropped in. The flex fuel injectors have a higher flow rate.

 

[Fless]

Rich in both banks? Could be leaking injector on both banks (not too likely.) Or misreporting O2 sensors.

I don't know if those vehicles have a way to reset the alcohol content? Could be as simple as that.

Wouldn't hurt to check for fuel pressure. Maybe for some reason the fuel pressure is too high? I can't think of a case causing this.

Is the engine, install and injectors original? My 99 Silverado has these two codes, but that's because I'm running a stock LM7 tune on the swapped L59 I dropped in. The flex fuel injectors have a higher flow rate.

x2 on the alcohol content and the fuel pressure. Read those if not to rule them out.