My car fires then dies every time - 1998 Volkswagen Passat

Time for a new key.

check fuse, check for fire, if no fire when turning over probably busted timing belt/chain, if fire then check for fuel

Have you checked cam timing?If it has jumped a tooth or two it will not start.

Sounds like your timing chain has jumped out of time, if the timing chain is old, the chain jump a few teeth putting it out of time having it fire at the wrong time when the exhaust valve is open. Check timing by pulling #1 plug - bring #1 piston to the top and line up timing mark , Ifind it easy to put thumb over spark plug hole and have someone bump the engine over and feel the pressure relief stop before you feel vacumm - timing mark should line up if the timing hasn't jumped

is it the car can't idle and when you step on gas pedal the die?

Back firing is usually an indication of a timing issue

The timing chain is most likely worn & jumped a couple
of teeth or the distributor was installed wrong,if you recently
had work done

you should use multi diag office i-2010 to check your engine and use this tool to clear fault codes.

Water entering cylinders.Head gasket blown.

back firing through d carb if so timing chain

The fuel pump is in the gas tank but there is also a gas regulator right at the front on the valve cover.