Replacing leaking fuel pump

[dictum]

You did not say what engine you have so I looked at all of them. If your 8th digit of VIN is a "Z" you have flex fuel and if is a "T" then is gas. The 5.3 engine had the two options. The 4.8, 6.0 and 6.2 engines do not show the flex fuel option. Just like @89Suburban said, the flex fuel has 2 lines out the top and the gas has 3 lines out the top. You also want to get the fuel level sender attached. Why they would offer the w/o fuel level sender is beyond me. Genuine GM parts numbers are MU1711 for flex fuel and MU2159 for the gas.

My 8th VIN digit is a "J"

It's a 5.3L of course

 

[OR VietVet]

My 8th VIN digit is a "J"

It's a 5.3L of course

That must mean that after 2006 they changed the designation for the engine. Unless someone changed it, if gas cap is black it is a gas engine and if yellow it is a flex fuel engine.

 

[dictum]

My gas gas is black.

 

[Fless]

My gas gas is black.

Color doesn't matter; it could have been changed. Mine's a Flex Fuel and came with a black cap.