I have a Tahoe Flex Fuel. When I take off from a stop, the first gear seems to lag and not have much power. When it shifts to second, it gains a lot of power and takes off. Is this normal? Would it have something to do with it being a flex fuel?

 

Nope. It's the Torque Mgmt system that limits power to protect the drive train.

 

You might try the Tow/Haul mode to see if it improves the way it feels