Fuel leak out exhaust-White smoke

[Quinton]

Our LS has been great over the past couple years. Ran perfect a few days ago but we went to use it today and...
Leaking fuel underneath the car from the exhaust and puffing white smoke out 1 of the tailpipes. When I revved it up it didn't sound or feel like it was hitting on all 6 cylinders.

Anyone have any advice or links?

Thanks!

 

[NateRW21]

white smoke in exhaust generally means you're burning coolant... or, basically... you have a blown head-gasket. Does this smoke have a sweet smell to it?

Also, it would be virtually impossible to leak fuel from the exhaust... it COULD happen, but is HIGHLY unlikely. IF it is in-fact fuel, you could have an injector that is stuck open

 

[Quinton]

I don't think it has a coolant smell, but it's defiantly leaking/spitting gas out of the exhaust pipe. Roughly in the middle of the car. I called my mechanic and he hadn't heard of it but he was guessing a bad fuel sender or bad gas with water that has an injector frozen.
I wanted to get the LS experts opinion based on past experiences.

(I did recently put in cheap gas)

 

[NateRW21]

Just about the only way for gas to be leaking out of your exhaust would be an injector that is stuck open. Possibly a coil that is not firing the plug at all. But this would throw a code. So absent of a code, and you're positive it is not a coolant scent, perhaps a seized injector. But this does not explain your white smoke; excess fuel would be a black smoke.

 

[Quinton]

I don't have a clue. My mech. is coming by tomorrow with his diagnostic to see if he can figure it out.

 

[Quinton]

His scanner didn't show anything so we just let it run. It started smoking worse. Then it finally started getting back to normal. He thinks maybe I got some bad gas and it stuck open a fuel injector.

It's running good now. Thanks for all the suggestions fellas!