1998 Nissan Pathfinder sputters

[osufan3108]

I have a 98 Nissan Pathfinder SE that sputters sometimes if I try and start it within about 30 mins of driving it. The engine is still warm. The sputtering does not last long, maybe a minute or two and then it's fine. My mechanic said it probably just needed a tune up so I changed plugs, wires and distributor cap. It ran fine for about a month but now it's starting the sputtering thing again. It's not every time I start it but enough that I want to get it fixed. Could it be a fuel filter, o2 sensor? Any other ideas? Thanks.