Not knowing where you live at makes it a little more difficult but if you live someplace with high humidity I would suspect excess water in the gas I would just go ahead and siphon the rest of the gas out if you don't have a whole bunch it to worry about and than throw in some injection cleaner and refill with High Octane gas.
You don't mention a Service engine light and that is why I didn't discuss a misfire such as spark plug or wires.I use to have a Nissan 280zx Turbo and if it sat for a long time the gas would get bad quickly in it. The gas may still be useable for another car as long as you don't see excessive dirt or rust in it or use it in a lawn mower mixed with some new gas. I like the Chevron system cleaner with techran in it or the Sea foam cleaners the best just pour the cleaner into the tank before filling with gas.
If the old gas that comes out of your car smells like turpentine ( Which means its real old) or has a lot of impurities in it, than dispose of it properly, and don't use it in any other engine because at that point its no good. The only reason I mentioned to run it in a lawn mower or another car is that the 350z is a high performance car and the gasoline requirements are usually higher and so what may just barley run in the 350z may run perfectly in normal car. Just cut it with fresh gas when using it.
yeah, would be easiest to get a tune up. Spark plugs do foul up and spark plug wires also stop conducting the electricity to make the spark. i was surprised by how many times I needed to change out spark plug wires in lifetime of a car.
But engine might also just be dirty inside. Go to walmart, go get the cheapest gas additive, looks like same bottle as STP, get couple bottles, pour into gas tank before you fill up gas tank, and drive car normallly for few weeks. The gas additive will clean out the engine on inside where spark plug ignites the gas.
Any burning will create residue, and in a car, it turns out to be what's called carbon, black stuff that collects inside the spark plug chamber. Over time, the black stuff coats the parts, and then the spark plug cannot burn the gas as well as when newer.
So couple bottles of the cheap stuff, less than $5 will help to clean the car, BEFORE you spend $300 on a tune up for your fabulous Z-car!! Hey, I've got a really nice and clean Toyota Rav4 I'll trade you for that badly running Nissan. I'm such a nice guy, I'll gladly give up my wonderful car to take yours off your hand.
But just try some gas additive for few weeks, see if it helps.
I say, few weeks, because the fluid will be in your gas tank for few weeks, for 2-3 tank fillups, it doesn't all get used up in the first tankful. But you should notice an improvement in just few days, if that's alll the problem is. But still, without knowing how you take care of the Z, a tune up would be good sometime.
A faulty spark plug or plug lead are the most common causes of this problem.
Could be your fuel injection or something to do with your spark plugs. Take it in. might need a tune up
is a check engine light on? a oxygen sensor will cause this. vacuum leak, injector problem. maf sensor
I have a Nissan 350z. And I noticed that my mpg has gone down. I used to get 20mpg and now I'm getting 14mpg.
The car also idles weirdly. And when I rev it, the rpms drop below 800 and the car starts to feel like it's going to stall, but quickly jumps back to normal idle of about 900 rpms.
The car hasn't been driven for 3 months though. Could this be the cause of all my problems? Should I give it a fresh tank of gas and drive it some more to see improvement?
