Bad mpg screen reading?

[Brankz]

So today I was driving and my mpg drop from 15 to 14,13,12 even when I was in full stop wtf lol
129973
Yea check engine and power light because I just made contact so dash will light up when I start the jeep no check engine light just saying lol

Disconnect and reconnect negative cable?

[Brankz]

Start going down like counting down

[htweelz]

Well if you just got gas and you are still it will go down. You're burning gas but not moving so the calculation of miles vs gallons will get smaller.

[Brankz]

Well if you just got gas and you are still it will go down. You're burning gas but not moving so the calculation of miles vs gallons will get smaller.

Fill the tank 2 days ago, I will disconnect the negative cable for 10 minutes and see what happen after that

[Panda]

If your in traffic or in town the mpg number will drop, if your at a stop light your getting 0 mpg

[Brankz]

If your in traffic or in town the mpg number will drop, if your at a stop light your getting 0 mpg

Oh really? So this is normal?

[toxicwaste29]

Well if you think about it. Your stopped and the engine is still running. Meaning zero miles per gallon. I have never had mine drop as fast as yours but it may depend how long you were at the light.

[Panda]

Oh really? So this is normal?

Yes, coast down a hill and watch it go up

[RMC2]

I never reset mine and it stays fairly constant overall.

My actual mpg does go up and down 1 or 2 mpg for the same commute, but it may be bacause I sometimes drive a little faster. Half of the 25 mile commute is 70 mph speed limit, most of the rest in 55 mph. So I am hitting a lot of drag.

[Wethy]

did you reset the mpg counter before this happened? because if i recall the counter is average not constnt. so if you had just reset it the number will rise and fall quickly. so if you did reset it then sat at a light or at idle the number would drop faster than if you hadnt reset it in a while.

[jeeeep]

that's normal, the longer you idle the more it drops.