Поплавок подклинивает или загрязнён

The fuel sender's float sticking on its guide, so the reported level lags or stops following the tank. The reading stays inside its valid range, which is why the module often accepts it and the driver simply sees a gauge that has stopped moving.

A float stuck high is the one that strands people — a tank reported as fuller than it is, with no low-level warning before the engine cuts. Stuck low triggers a warning on a full tank, which is a nuisance rather than a risk but sends people to replace a perfectly good sender.

Deposits and debris in the tank are what foul it, along with a bent arm from a careless pump replacement. Watch the reported level across a full refill rather than at one moment — a value that jumps, sticks, or does not track fuel going in is the finding, and no static test at a single level will show it. A fouled float argues for inspecting the tank, since whatever coats it also reaches the pump.