fuel tank 305 full tank
 

hey guys so a month ago i had a little incident with my car and the majority of the bottom had to be redone. exhaust, floor, cats etc. the gas tank got dented and had to be replaced. the car wasnt driven for a month. i got it back 2 weeks ago and usually when i fill up i get about 335-345 miles full tank. ever since i got it back...full only goes up to 305 and also the miles indicator can keep dropping but the dots stay full. so im down to 265 miles but the dots still indicate a full tank. the shop said jus let the car get back to its driving cycle...for a few thousand miles then itll go back to normal...anyone experience this issue? like today i was down to 35 miles and the low fuel indicator started blinking but i had 2 dots left....2 dots with 35 miles...weird! this is my 2nd time filling up since i got it back. im getting 16.2 mpg before i was getting 18.4

You have a 19 gallon tank. See how much fuel you are putting in it when it says it's empty. Then just do a little math and see how many gallons you had left and drive it like empty with a gas can just in case. But calculate mpg based on initial fillup so that way you've gotta ballpark of how many gallons are left.

it filled up at 17.5 i think it

and i get 16.2 mpg

Ur driving style changed. Quit pushing that gas pedal so much.

:iagree: bouncing off the rev limiter to show off your exhaust will do that your mpg.

Dang, I wish I could get 16....only14 in town, dam TT won't let me do better :icon17:

It's possible that the primary O2's were damaged -- I had a problem with a bad O2 and had a corresponding decrease in MPG.

for all of u that said i drive it too hard and stop bouncing it off rev limiter...ive redlined my z once since i got it...i drive normally and shift at 3.5k so before u assume get the facts.

OP I think they were being facetious...Don't take things so serious or you might have a bad time on here and not get the good responses you're looking for...Either that or invest in a good flame suit :tup:

We all take a little ribbing at times, but you will get good to great advice if you are patient. Jordo advise I would pay attention too! Also since you got a new exhaust system you may be running rich and that will lower your mpg's. You should think about get an tune. Really, you are not that far off if that is city driving alone.

thanks
 

yeah i think o2's are fine i have a buddy who works at nissan check the car out for issues every month he said its all fine. im getting uprev tune next week. thanks for the advice

Shifts at 3.5K :roflpuke2:

See there's ur problem u shift at 3.5k its toooo high try around 2-2.5k only 1st gear goes up to 3k, i actually shift around 1.6-2k rpm some times lower, but thats cuz ive adjusted my a/f table to give me more torque in low rpms,

ur running 14.7 a/f ratio(stock) all the way to 3.2k rpm, u have noo torque car is slow. I know i hate that, but if u wanna save gas ull have to reach desired speed sslloowweerr.

The O2's are pretty sensitive. If your originals were fine, removed, and re-installed, that alone could have damaged one.

My problem was a bad heater wire on the sensor after removal and re-install for headers. The O2 couldn't heat up enough to get out of the warm-up cycle. The result was mpg like yours and an intermittent stumble at idle.

Weirdly, it didn't happen right away -- it got gradually worse over time -- and other than the mileage and occasional stumble, it ran fine.

If you have a buddy at Nissan, ask him to hook up Consult III and monitor the O2 voltages, heater corrections, etc to make sure all is good.

Good luck!