Like all good things, it does eventually come to an end.
Almera's are getting few and far between. N15 are rusting away, and N16 are being tucked away in a pensioners garages, or getting scrapped due to timing chain issues.
You're meant to get a woosh of air when you remove the fuel filler cap.
I have known of the n16 fuel filter clogging ( integral with the pump ). It also sounds like a failing fuel pump.
Its all under the back seat bench, so have a look.