Sh*tty MPG, need inputs...

[AznRide]

On my 91 240sx, from driving around 23 miles, I can actually see my needle goes down a little (half way at full to the next mark). So i'm guessing I would get around 20 mpg....that is terrible. I know the car is running rich because I can smell it. Does anyone know what's wrong with it?

[Structure240sx]

could be a bad o2 sensor

[trpower7]

Mad gas mileage is any of the following1) Bad O2 sensor2) Bad Coolant Temp sensor3) TPS4) MAF5) AIV6) Bad injectors7) Bad Injector Seals8) Bad FPR (fuel pressure regulator)

Any of those things could cause it, although if you can smell it running rich you can rule out injector leaks. Start testing things and crossing them off the list.

[Holisticbeatz]

How many miles does your motor have?

[AznRide]

147K. Thanks guys

[rschwalbe]

So far I have replaced the following:

1) o2 sensor2) Coolant Temp sensor3) plugs4) Injen cold air intake w/ K&N cone air filter5) Fuel injectors6) Complete tune-up and oil change

Verdict is not in yet but I can tell you that since I have done all that the car is running 10 times better!

Running Super (93 octane) since this has been done and the first half tank wasn't great but better than the 100 miles I was getting per half tank (came out to about 130 miles on that half).

Next thing I am doing is a CatBack!

[UnderPressure]

i would try an ignition system (plugs, controller, coil and wire)this will increase your mileage reguardless of wht the problem is and may even fix it completely if the problem is in the ignition system