Timing belts are every 60k on our 4G63 stuff. Unless it's different on your 4G64 that doesn't seem to match up. Is that thing an interference engine? If not I wouldn't even worry about the timing belt, but this light might be a good sign to waste a few hours and a few bucks at discount to replace some hoses/belts/plugs/wires/distributor cap/ etc, whatever catches your eye as a likely candidate.