Sentra dies once it warms up

SOURCE: 1987 Nissan Sentra Wont Start (died after going through a puddle)

the EGR (exhaust gas recirculation) valves like to stick on these cars, they get fouled up with carbon and if they get stuck open, the car will not want to idle well and even stall out. they are vacumn operated and can usually be cleaned with some carb cleaner and small picks. before you clean it, try moving the diaphram up with your fingers and see if it comes back down. this will tell you if its stuck. the EGR manifold port can also become clogged solid and requires removal for cleaning.

SOURCE: 2004 sentra dies on freeway

sounds like fuel starvation...check the fuel filters and the fuel pump

SOURCE: A 1985 Sentra - The engine idles until warm then it dies.

has it got a idle control valve, have tried adusting throttle cable slightly

SOURCE: 2006 Nissan sentra 1.8 Will not start cold Has

There is a problem with the fuel pump. This is a known problem with the 2006 Sentra and the dealer should have known this. Get your money back

SOURCE: once my sentra has warmed

Nissan has a lot of problems with their fuel pumps. If you have it replaced, it will fix the problem, they actually have a kit for most models they use to repair the problem. While they have had a lot of problems with the fuel pump causing hard starting, etc., not enough to make it a recall item and therefore typically is not covered under warranty.