skipping and sputtering

my b18a1 is starting to skip an sputter and i have noticed that it is atarting to back fire. Does anybody have any idea what would cause this? Does anyone know how to fix this?

check fuel pump, fuel filter, lines, injectors, and ignition timing... usually the causes...

In order of normality:
1. Ignition parts/timing
2. Injector(s)
3. Clogged line/regulator/filter
4. Pump

how do i check the ignition timing?

timing light