vacuum leak, moisture/oil in the spark plug wells, (he's got a 1g btw, so it's not a 420a for whomever posted that...not a widebody neon), bad plugs, wires, coil, etc....also, just 'cause wires are fairly new, doesn't mean they're functioning properly. however, i'd check for vacuum leaks if swapping plugs/wires doesn't fix the problem.