How to test the Ethanol % in your fuel - and when/why you should?

[08z71bgm]

You might be surprised about that if you have hptuners and look inside the ecm. The 02-06 Tahoe vin Z was flex fuel. Most likely uses the same ecm as the c5.

They both use the same ecm. ACDelco number 12200411 is for c5 and Tahoe. If they have the same ecm they have the same capabilities. What you need to know is what pin is for the signal to the flex fuel sensor. Once you know what pin it is then add it and put the flex fuel sensor between the rail and hard line. After that is done you can turn on flex fuel using hptuners then you need to tune for it.