When my 1991 pathfinder warms up it starts sputtering when driving it. When its cold it doesnt do it as bad. I have taken it to a mechanic and they havent found anything wrong with it. If anyone has any ideas what it could be that would be awesome. its a 1991 xe with a 5-speed tranny.

How many miles? When were plugs and wires last changed?

175k and i havent changed them since i bought the truck, i did have the exhaust redone its straight piped with a tip, no cat.