Nissan Repair: 2002 Pathfinder Issue, timing belts, fuel system

Question
Recently my Pathfinder has started choking and jerking.  If I get up to 70 MPH it becomes worse.  Even while parked and idling, it will start this jerking....usually in the back left section of vehicle.  The mechanic replaced a sensor.  It has been in the shop four weeks and no one can determine the cause.   Could it be timing belts... stopped up fuel system?  Transmission?  I am at a loss on how much more to invest in this vehicle. The only recalls I see on this make has to do with lighting.  Not sure what step to take next.  Thank you for any suggestions!!

Answer
Alfred,

If the jerking is a stumble you are looking at the ignition system.  Probably the distributor is defective.  Have the distributor looked at for oil in the optical shutter wheel.  A coil could cause this too.  Does the vehicle have the check engine light on?  If so, email me back and let me know.