Suddenly on my 2015 Monte Carlo with the analogue fuel gauge has gone weird.

Today it was showing just above the Red but the fuel light was not on yet.I put in just £5 ( yeah i know but its middle of the month) and the needle hasn,t moved from where it was.Tonight again i thought i would just put in another £5 and still the needle stayed put just above the Red but as i was driving its very slowly beginning to creep up.

Before this happened if i put £5 in it used to instantly go up at least 3 lines on the gauge yet now this happens.

Any ideas please?

Sudden faulty fuel sender?

Disconnect battery for a while and reconnect to see if it resets everything?

See how you get on at payday when you fill the tank or take the gauge well passed the low positions, things might free up with use and out of sticky range.

It's the modern way - the fuel gauge fronts gubbins that smooths out small changes so that fuel gauge won't move around wildly. SO if you put a small amount of fuel in it may not register. I've experience this with a few courtesy cars where I just put in a few litres to cover a relatively low mileage covered - I always get a receipt to show the dealer but the gauge doesn't always seem to move.

Edited 19 October, 202519 Oct by bigjohn

When you park up or downhill the fuel sender fluctuates as the level inside the tank moves around. The ECU knows this so when you add a small amount of fuel it assumes the level change is probably due to an incline so it's calibrated to not show it immediately - though it does register it slowly after driving a few miles, as you've seen. If it didn't use this logic, the gauge would be up and down every time you hit a slope.

Put in a bit more fuel when funds allow and it should behave normally as the amount you are adding exceeds the differences from being on a slope, so it knows you've refueled..