Erratic Guel Gauge
 

Can anybody advice?

When I have e.g. 1/4 fuel left in the tank, and the car is parked with the front sligthtly downhill, the fuel gauge indicates zero it the ign. is switched off and on again.

This also switches on the Check Gauge light.

When I start driving, the Fuel Gauge remains in Zero position. I have to switch off and on the ign.in horizontal or uphill position to get the reading right.

I can see the same when the tank is full, and it reads apprx. 1/4 tank lower than it should, and do not come all the way to Zero.

Any idea??

Sender unit
 

is 15 ohms empty and 170 ohms full. Only known problem is the sender floats that develop a leak and sink. I park on a slope and my readings vary from level ground. This has a long tank and is prone to that. Is this something you just noticed recently? There is an anti slosh electronic module which averages out the reading to keep the needle from bouncing. Mine takes several minutes to read correctly. Never tried it but I would imagine if I moved to level ground and restarted, the needle would then read that level and then start to average.

Thank you Opera.
This car is quite new to me, and I noticed recently. I need to follow this up so try to find a pattern of it's behaviour.

Maybe it is the "anti slosh electronic module" you mention?. I find it strange that the gauge is not moving when the car is moved from the sloop to flat terrain. Seems like something needs to be reset, and maybe it is the "anti slosh"

Do you have any idea where it is found?

Only thing you have to worry about is getting low on gas. I never let my 97 get below 1/4. I even ran out of gas in my driveway once when I was letting it warm up. Adding 3 gallons of gas made the gauge read 3/8 on level ground. That isn't much of a safety margin. The fuel pump is cooled internally and externally by the liquid. Keeping it covered will extend the life of the pump. This is a very long narrow tank with the pump about in the center. Take a tall bottle which is 1/4 full and put it on the side. Tip it just a little and see what happens to the level in the center. The gauge is acting as it should. I wish my boat gauge was this smooth. On the other end, you can add a lot more fuel after the gauge reads full.

Opera.
You are right. The simplest thing is to fuel at 1/4 tank, and it will be OK, also it will be safe for the pump. As you say; the long tank is the reason. It is no problem to live with it.

Have a nice day.