studder @ low rpms... help?

[SoDelMotorsports]

hey whats goin on, the car im having the problem with is a 91 240sx with ka motor... automatic trans.. lately this has been getting worse little by little, it started off with just a quick studder every once in a while only while i was stopped with the motor under load like a red light or stop sign, now its been going into low rpm (-2.5k) accelleration with a sputter one after the other sometimes, but its getting more frequent... anyone have this same problem and maybe have the fix? thanks

[mexicanracer03]

check you spark plugs, cap and rotor button. and then check and see if you have a broken or loose vaccume line.