Pontiac Repair: 2005 Pontiac Grand Prix misfiring and smells like gas, fuel pressure regulator, pontiac grand prix

Question
My car was misfiring and stalling so I brought it to the garage.  They replaced the catalytic converter and O2 sensor, and said the plugs needed to be changed.  Since they wanted $300 to change the plugs, I let them do the other work and bought and my husband replaced the plug wires since two were broken off.  The plugs seem fine, but the car is still misfiring and smells like exhaust and gas.

Answer
Hi Lori:

well first off I would checkto make sure you have spark on all 6 cylinders. If the engine is not firing on all 6 that will cause the gas smell and black exhaust smoke... You can get a tool called a spark checker to test this it's a cheap tool.. Another thing to check is if the fuel pressure regulator is leaking gas into the vacuum line for the regulator. with the engine running pull the vaccum hose off the regulator ans see if there is raw fuel being sucked into the vacuum line that can cause a misfire as well. These things are where I would start looking. Good luck :)