When I use the heater, I can smell gas (did not smell with AC) and the mileage goes down significantly. I cannot think of any way these two are related but that is what is happening. Please advise.
Heater causing gas odor and low mileage??? on 1995 Chevrolet Monte Carlo
AGREE WITH #1
1 more answer , 3 more comments
You need to get this looked at ASAP. Sounds like you have a fuel leak under the hood such as a ruptured fuel line. Obviously, if you are leaking fuel, your mileage will suffer. You smell it with the heater because the intake for the heater is right behind the hood and in front of the windshield and heat usually pulls air from outside unless set to recirc. A/C on max will use recirculated air automatically which is why you don't smell it then. But seriously, get this thing to a mechanic before it decides to burn to the ground.
I will, but why does the gas mileage not change with AC or no heat but I lose 80 miles or more per tank when I use the heater? Never see or smell fuel when the car is idle in the drive way either.
Just get the leak repaired and we can go from there on the mileage loss. All you need is one bad plug wire under there with the fuel vapor and you will be getting fantastic mileage walking.