car won't rev past 4-5,000rpm

[sway2this]

i have a 96 gs 2.0.
i cranked my car this morning and when i was goin down the road when it got to 4000rpm it started sputtering and wouldn't go past.
it just started this, this morning.
could it just be a sprkplug or somthing.
i'm prob goin to the parts store to get some spark plugs for it!!
appreicate any help.
charles

 

[Denji]

any smoke from the exhaust?

 

[Defiant]

First suspect is plug wires. Open the hood in the dark and look at it while it's running.