I've got a 2003 Monte Carlo with the 3.4 engine with around 140,500 miles give or take. The car has had this hint of gas smell for a while but I wasn't able to figure out where it was coming from till the other night when I finally discovered that the smell appears when the car is idling at anytime and when it does it comes very strong through the cabin of the car. Before I take it to a garage I am trying to get an idea of what might be causing the problem I had a friend tell me that his father had the 3400 in a Grand Am and when it was doing the same thing that it seal in the piston that went bad and ended up overheating the whole engine and warped the cylinder before the car went to the junkyard. Any help with this would be greatly appreciated thank you

 

You could have a faulty fuel pressure regulator. When this part fails, fuel flows through the vacuum line into the intake manifold and the presence of this fuel gives you the smell. If you pull the vacuum line off of the fuel pressure regulator and fuel drips out of the line, no matter how little, then that's what it is. Hope that helps