P0172 P0175

[Joseph Billeter]

Okay so my gas mileage straight dropped within about a month and it’s lost it’s power recently. Those 2 fault codes showed up and I had a crank position relearn done and cleaned MAF. It ran best it ever had in years and now it’s back to crap. Any help? 

[chem_man]

P0172 is a code indicating that one or more of your fuel trims is running rich.

P0175 is a code that indicates that the fuel trim for Bank 2 is running rich.

 

So, for some reason, your engine is putting more fuel into Bank 2 than it needs to run properly.  You might have a fuel injector that is sticking open, a spark plug that is not firing, etc.  Or, it could be something with the AFM system.

 

You need to do some detective work in order to diagnose what is going on.

 

Good Luck!

[dsr611]

5 hours ago, chem_man said:

P0172 is a code indicating that one or more of your fuel trims is running rich.

P0175 is a code that indicates that the fuel trim for Bank 2 is running rich.

 

So, for some reason, your engine is putting more fuel into Bank 2 than it needs to run properly.  You might have a fuel injector that is sticking open, a spark plug that is not firing, etc.  Or, it could be something with the AFM system.

 

 

OP didn't say which vehicle this was occurring on, but if it's the 06 in his profile, it won't have AFM

[chem_man]

Thanks for letting me know about the 2006 5.3 not being AFM.

 

I assumed it was the OP's truck listed under his name since this sub-forum is for 1999 - 2013 Silverados.