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ASE Master Guru
ASE Master Guru, ASE Master Tech
Category: Chevy
Satisfied Customers: 208
Experience:  General Motors Engine Performance and Diagnostic Certified
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I smell gas mileage has dropped, the car is also running

Resolved Question:

I smell fumes in the car and my gas mileage has dropped, the car is also running at about 170 suddenly instead of 200...please help
Submitted: 5 years ago.
Category: Chevy
Expert:  ASE Master Guru replied 5 years ago.
Ok. First off if your smelling gas you need to have this serviced immediately. It is common for the fuel pressure regulator to fail on this model.If you are mechanically inclined I can help walk you through diagnosis and replacement. Locate regulator on top of engine attached to fuel rail, remove vac line and inspect for fuel leakage from regulator. You may need to start car to observe leak. Let me know what you find. P.S. if you are not mechanically inclined I suggest finding a reputable repair shop and have it serviced ASAP.
Customer: replied 5 years ago.
My Fiance is pretty mechanically inclined can you give anymore info that will help him? Also, if it is something I have to have someone repair, what would a fair price for that type of work be? And do ALL of my car's symptons fall under this one fix? The low running temp can be caused by this or is that a whole other problem.
Expert:  ASE Master Guru replied 5 years ago.
Certainly. On top of the engine attached to the fuel rail is the fuel pressure regulator. It will have one small vacuum line attached to it. These regulators are known to fail internally resulting in heavy fuel consumption and possibly strong gas smell. It is possible that you may have another issue but the regulator is a very common failure. Go to this site ( to see a picture of the component I am referring to. It may look slightly different depending on which engine you have. If you have further questions feel free to ask.
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Expert:  ASE Master Guru replied 5 years ago.
Did the information I provided assist you or do you require further assistance?
Customer: replied 5 years ago.

I took the car in and they said I needed a new thermostat for the Coolant system. They said the pressure regulator for the fuel was fine and they could not find any drips or leaks of fuel, I do still have a slight smell of fumes sometimes but not consistently. The shop that fixed the car stated the fact that my thermo had failed caused my engine to use more fuel (like a choke or something) and that is why I was smelling the fumes. Does that sound reasonable to you? Or do you think I should continue to worry about it?

Expert:  ASE Master Guru replied 5 years ago.
The t-stat can and will negatively affect fuel mileage if defective. As far as the fumes go, you should not be smelling them inside the car, period. I am unsure what you are smelling, I am assuming that it is gas fumes. Is this correct?