The fuel injectors can fail and cause drivability problems. Often there is no Check Engine light and the failures can be caused by corrosion of the connector, clogging beyond the point of cleaning, and/or internal failures.Google+
Car Problem Reports
Nissan Xterra Fuel Injectors May Fail and Cause Drivability Concerns
Nissan Xterra Problem
Engines Affected: 3.3L V6, V6
Average Mileage: 114,810 mi (15,045 mi - 178,880 mi)
Visitor, 2002 Nissan Xterra, 3.3L V6, 89,000 mi
Put my 2002 xterra 3.3 on a computer and the readout said # 2 cylinder misfiring. changed plugs and wires and timeing belt rotter butting and disterrabor cap and it still misfiring on # 2 cylinder. I have ran seafoam cleaner through the tank two times helps sometimes. what next ?? Jimmy
Visitor, 2001 Nissan Xterra, 3.3L V6, 165,000 mi
Clogged fuel injector causing rough idle, fouling O2 sensors (which causes check engine light) and lowers gas mileage down to 11mpg.
Visitor, 2001 Nissan Xterra, 3.3L V6, 178,880 mi
Same problem an that's just one of many
Visitor, 2000 Nissan Xterra, 3.3L V6, 160,000 mi
Not fixed yet. Misfire on Cyl 4
Visitor, 2004 Nissan Xterra, V6, 45,750 mi
Problem with fuel injectors. Engine light did come on. Luckily covered under warranty.
Still is not repaired correctly. 2 years now - emissions problems. Have had an oxygen sensor replaced, all spark plugs replaced, numerous other things (hoses, belts, timing belt, radiator, power steering, center link and idler arm) just to name a few! I need help. Auto Zone codes say Knock sensor or misfire # 4 cylinder or Catalyst system efficiency below threshold. But mechanics can't seem to fix it and keep the check engine light off more than a week. It runs a little better with a full tank of high octane gas.