LS1 HOSS

Ok so i've been having a problem, when i drive my car probably at least 12 miles or so at least 2 or 3 of those miles the car will run rough,the idle will drop to 400, it pops when you step in on the clutch and you can smell gas and fumes that are bad enough to make your eyes water. Its starting to get black marks on the bumper from this, seems like its dumping gas or something. I put in 2 fresh front oxygen sensors and had it tuned and it was good for about a week and then the ses light cut back on and it started doing it again.

So i have the 2 code numbers and they are P0131(bank one,sensor one,circuit low voltage) and P0135(heater circuit malfunction). Anybody have the same thing happen? Its very annoying