Just curious. i know my car is old, but my mpg is crap!! i think i get bout 150 per fill. i hardly drive it as well. my idol takes a long time to drop. throttle acctuator was replaced, & car was tuned up. any inputs would be awesome!!

 

what year is your car? auto or manual?

 

04 coupe auto. 56000 miles

 

maybe your fuel injectors have a problem. I have 06 6MT and I get approx 21mpg in city. Maybe your engine is running rich. Check your filters, as well as tire pressure.

 

You said you only get 150 miles to the tank.... About how many gallons does it usually take you to fill it up? Maybe you have the Fuel-Filler-Neck problem where your car is not letting you fill it all the way to the top. If this were the case, you'd think the car was full when it was only about 3/4 full. Assuming your fuel gauge is working properly though, it would show 3/4 full instead of showing completely full if this was the problem.

In the meantime, check to make sure your air filter is clean and spray some MAF Sensor cleaner on your Mass Airflow Sensor.

 

1) Your car is not old.
2) It sounds like there is something mechanically wrong with it. You said it was tuned up, what exactly was done? Did this problem start after it was tuned up? The idle should drop and be steady once it reaches operating temp. If it doesn't there could be air in the coolant or a bad sensor. Can you check the spark plugs and possibly post a pic of what they look like? Like the other guy said, X amount of miles per fill up doesn't mean sh_t. Divide the miles driven by the gallons filled and you'll have an accurate mpg figure to share.

You really gotta post a little more information before we can start to try and help you

 

I have receipts from previous owner that the plugs was changed, oil, and air filter. Maybe I'm just not used to the car idling high at the beginning. Thanks for the info guys

 

okay.. 56k and already a plug change? did he service it at a dealer or a small general shop? because they could've put in a cheap plug in there..

also.. how long do you idle in the morning? shouldn't be more than 30 seconds, if that..

where is your idle after 10 mins of driving? should be around 700 rpm.

 

Another good question: How hard do you drive the car?

I can cruise around in the G and make a 1/4 tank of gas last two days if I have to. Or, I can go out and burn through it in 15 minutes.

When I've seen fuel consumption issues this bad on most Nissans, it's usually a MAF issue. Not necessarily a dead MAF, but a MAF that's either extremely dirty, or on its way out.

 

yeah. i had the previous owner change the plugs cause the valve cover gasket was replaced, i had my own mechanic check it out,& he also said it's probably age that is making the idle take bout a minute to settle down. I guess here in hawaii, to many stop, & go's, but i don't really speed. this is the "cruise"car. thanks for all the info guys

 

a brand new G35 takes a minute or two after a cold start for idle to "settle" down..

i think you are good man.. enjoy the car.. and try cleaning your MAF like someone suggest..
and pump that Premium gas in there..

 

maybe your o2's are out? but 150 per tank is just horrid, maybe clogged air filter, fuel filter, or bag injectors.. when car is all warmed up does it still smell like fuel?

 

i had everything checked out, & all is good. I am going to drive my g for 2 weeks, & see whats up. I'm actually wanting to sell it soon, & get a 37. But Nothing feels better than cruising in a G!!! i'm going to put in fuel additives, & see whats up, it helped my 07 sedan, & my 2010 tl. hope this does the trick. thanks again for all the input