ok, so i got my car not to long ago and i noticed something weird. when i put gas in the car the needle take a long time to go up to where it has to. and when im driving it goes down alittle (and sometimes alot)and then goes back up. thats never happened in any other cars ive driven. so i wanna no if its a common problem, or if there all like that.

 

It does take a bit for the gauge to react to fuel level, yes. It's designed to basically 'buffer' inputs and wait so it doesn't jump all over the place when you take a quick turn, etc.

When the gauge starts reading lower, is it when you're in long, sweeping turns? Driving up/down long and/or steep grades?

 

well it goes lower when i take the car over 4000 rpm but not over 5000. i rarly take it past 5000. it goes down and then when i go to a stoplight i notice that it goes back up allitle.

regarding the reaction time with fuel fillup. do you no if there is a "mod" or something similar to "change" that. because my previous car(an 06 corolla)
when i would fill up with the car off (obviously) and i would turn it back on it would shoot up to where its spposed to be.