what can i do to stop my 300 from burning too much fuel?


Asked by Jan 12, 2008 at 12:03 AM about the 1986 Nissan 300ZX

Question type: Maintenance & Repair

13 Answers


My first response is to say dont drive it (making a joke), but if you can smell fuel, you have a leak some where, check the tank and lines first. After it sits for a bit check for puddles, also check once you park it, gas evaporates but it will puddle if there is enough of it. A spark can start a fire, be carefull and try not to drive the car until you get this looked at. You may need to take it in and get it looked at. But if you can smell it dont drive it. Hope this helps, all the best.


In addition to what Casper suggested, I would suggest a tune-up, new fuel filter, and new air filter for starters to increase your fuel economy. Check tires for proper inflation as an underinflated tire will cause fairly sizeable loss of gas mileage. You don't mention if you feel your problem is mechanical in nature, or merely a question about how to increase fuel economy, but between the two of our suggestions you should have a good start to making it a little better at the pump.


well thanks i have had a tune up and it runs well but i have been told that either my feul regulator or my computer is off my 300 is a 86 i am lost i dont know what to do i smell gas every now and again but i am not getting the milage i should

1 of 1 people found this helpful.

The z31 (1984-1989) 300zx had to have a fuel injector recall done back in the late 80's. If this recall hasnt been performed. Your engine bay WILL eventually catch fire. What happened was, the fuel type was switched back in the 80;s and began eating away at the glue in the injectors causing them to leak. I have seen this happen on countless cars, and caused them to catch fire. Take your car to a local nissan dealership, and they will check to see if the recall has been performed using your VIN number. If it hasnt been performed, the nissan dealership SHOULD perform the work for free. If they refuse argue with them, because they are obliged to perform this recall.

1 of 1 people found this helpful.

all kidding aside, if you really just want to get gas mileage up, buy a different car. 300Zs are pretty well known for being gas guzzlers


i had a 1990 300 and she loved to drink gas, i had a mild fuel leak and would smell fuel when i drove the car i want and had the gas line repaired and it helped the problem, also just babying the throttle will defiantly help out with fuel economy

2 of 2 people found this helpful.

check for recalls. We had a Maxima wagon years ago (same engine as the 300) and it leaked fuel also. Mom went to fix it and SURPRISE it was covered under a recall and repaired free of charge.

1 of 1 people found this helpful.

best and only thing that will make a really noticeable difference in mpg, is your driving habits. try to accelerate easily, and coast to a stop when possible, for example, if you see a stop sign 500 feet ahead, let go of the gas and coast to the sign, using the brakes as little as possible, every bit of the cars speed that is being taken by the brakes is speed you had to use fuel to get. all within the boundaries of safety of course...


Another big help would be changing your oil. If you have over about 150,000 miles or so, "high-mileage" oil would provide the biggest gas mileage boost


try putting in a new o2 sensor, could be running lean because of a bad o2

2 of 2 people found this helpful.

I put the lucus the new one in from wal-mart, made it run better too, 8.95$


There is a recall on the injector system by Nissan. Recall number 951006000 will replace all the injectors and related hoses. Call 1-800-647-7261

1 of 1 people found this helpful.

I agree with Adam. Start with the O2 sensor. A bad O2 sensor can cause a lean burn situation and the engine can run hot. If the sensor is dirty, it can cause a rich burn condition that can plug a catalytic converter. The difference can be as much as 30%.

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