# low fuel milage and fuel smell



## newbie81 (Feb 20, 2011)

I am trying to find out the most likely reason for running rich. my 86 n/a is showing 30ish mpg on the dash when driven gently. I am only getting about 20-22. and I get a rich fuel smell off and on. gets worse if I give it more throttle. I fixed all vac lines, found one bad one, fixed it and milage got worse.


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## smj999smj (Jan 1, 2006)

I would think 20-22mpg would be typical mileage for a 300ZX. The question is, are you running rich or are you smelling raw gas or gas fumes? If you can find a shop with an exhaust gas analizer, you could know for sure if you are running rich or not. Typical problems include a lack of vacuum to the fuel pressure regulator (disconnected/leaking or clogged/collapsed hose) and bad oxygen sensor. Obviously as far as leaks, anywhere on the fuel line can leak, but check the fuel injectors and check for rusted fuel lines.


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## newbie81 (Feb 20, 2011)

no luck with the gas analyzer around here. I was getting better fuel mileage a few weeks ago. checked the fuel lines and rails, no leak. got codes for chts and fts. could these effect enrichment all the time, not just when cold or hot. I have noticed if I put my foot in it I believe I'm loosing vacuum. my hvac puts out hot air, doesn't matter what I have it set on. But I just replaced all vac lines, did it one at a time so as not to mix anything up.


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## AZ-ZBum (Nov 21, 2004)

Don't read the gauge to determine your MPG. It's not reliable or even remotely accurate.


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