Fuel gauge reading incorrectly

I've got a problem with my fuel gauge at the moment, the gauge is reading about 1/4 full when the tank is full I drive 50 miles or so and the light comes on and the computer tells me it's time to fill up again, if I go up and down a sharp incline the gauge seems to go back up agian for a while would this be a problem with the sender in the tank? float sticking or something?

Certainly sounds like the most obvious place to start, with the in-tank pump.

Is it a Classic or P38? The Classic is a lot easier to work on is all.

It's a 4.6 P38 so don't really want to have to worry about the fuel situation (well more than I do anyway!!!)

Ah, if its a P38 you'll have to wait until you've a nearly empty tank and then drop it to get at the pump, but I guess as you have the 4.6 you won't have to wait too long...

But there is the quandary.....how (short of running out of fuel) will I know when I'm nearly empty!!!

Dip stick...... seriously? you wont really will you? you'll have to fix it

No really................

I'm guessing you get 200 miles from a tank full? So after about 150 miles it will be just about light enough to drop without squashing you underneath it.

Best thing to do is carry a spear can around in the boot just in case

Or run it empty then fill up and put your mileometer on to 0 and see what you get, and work it out form there

I average about 20mpg and the v8 has a 100 liter tank (22 gallons) so that comes out at closer to 440 miles even if I put my foot down a bit I would rarely see less than 18mpg and that still works out at 396 miles!!
Not brilliant but not as bad as you think!

All things considered that makes your V8 cheaper to run than my diesel. I remember when diesel was 36 pence per litre, ah for those days again...

Traditionally (Huh!!) Diesel was ALWAYS cheaper than petrol in the U.K. but everyone cottoned on to the fact that it was cheaper and you got more MPG out of the stuff, so everyone went and bought diesel cars, then the government lost revenue because of that, and hiked the tax up on it

What mpg do you get on your diesel then . Imust admit I thought it would still be cheaper to run even with the price hikes!

I think what I will do is fill up again and then run for about 350-380 miles then sort the problem out!!

In the past diesel was always better for MPG, petrol engines now are a lot better now than they used to be