2011 Silverado, 1500, LT-Ext. Cab, 5.3 Liter, FFV. 40,000 miles.
I recently got 2 codes for fuel issues (P0172 & P0175). Brought the truck to my mechanic and he said the throttle body was very dirty. He cleaned the body thoroughly and changed the mass airflow sensor. He said this was a result of the gas I was using and suggested I stick to a brand name like Exxon, Sunoco or Shell because of the additives that help keep the motor clean. He also suggested that I use a fuel injection cleaner to clean the injectors as well.

My questions are :

1, Is he correct about the brand of fuel I use (currently Delta Gas) because it's a lesser quality with no additives?

2, Because this is a Flex Fuel vehicle, what is the right fuel injector cleaner for this type of truck ? The mechanic said that some cleaners shouldn't be used because of this. I want to prevent this from happening again.

Thanks for your expertise.

 

No matter what you read, cheap gas brands have the nminimum amount of detergent in the fuel. Mobil,, Chevron and Shell are much better then crap gas like ARCO.

You get what you pay for. Why is cheap gas less expensive? Becuase they use inferior blends of gasolne.

 

the most common cause of rich fuel trim on both banks for a flex fuel vehicle is a skewed flex fuel sensor reading. check the flex fuel sensor value with a scan tool...if it doesn't match the ethanol content of the fuel that you use...it will overcompensate and add to much fuel.
so ...if you don't use flex fuel and use 87 octane...the flex fuel reading should be around 10%

custom cai set up can also skew the feul trim.

 

What would the pcmc and what would it do if the flex fuel sensor was completely disconnected?