I have a 2008 GMC, with flex fuel 5.3 liter and having some rich fuel mixture issues. I’ve been down the list of things to check and have replaced a few items.

One thing i was told is that the this truck sometimes needs the fuel composition reset. Apparently you can not reset this by clearing the MIL or taking the battery connections off.

I want to verify that my truck is assuming it has a high alcohol percentage. If so i can take my truck in and have them reset it.

Is there PID for this? i know there is one listed in the torque app but it doesn’t see this information.