I bought my first tahoe last week. It's an 07 LTZ with 20,000 miles on it. When I bought it the salesman told me if I want to burn E85, make sure that there is less than 5 gallons of gasoline in the tank before filling with E85 for the first time. Supoosedly to allow the computer to learn how to burn the E85 correctly. I though it sounded like a bunch of bull****, and could not find anything in the owner's manual to back him up.

Is this true? Seems unlikely to me that the ECM isn't already factory programmed and capable of effectively burning the E85.

Locally E85 is $1.69 and gas is $2.05. If E85 causes a 30% drop in mileage it's not worth it economically. I just want to try it because I can.

 

Yea, I dont think it matters,. My Tahoe can use it but I have never tried it either. I dont know much about the stuff though. Id rather use gas while its still available. Then Ill go electric.

 

I have not tried E85 but have also heard that you should have a pretty near empty tank when you fill up with E85 AND you should also be prepared to drive it a bit to get the fuel into the system as I have heard there can be hard starting issues if the system has not had time to adjust for the alcohol.
Search the forum for E85

 

I guess it does matter, Thanks!