97 Nissan Terrano/Pathfinder 3.2 diesel. Started doing this hesitating, bucking and jerking thing at startup. Doesn't do it all the time. Usually when cold. Once started, the engine runs fine. Battery is fine. Suspect a starter motor or solenoid. There is no grinding or gnashing noise, just this kind of hiccup as it turns over. Any ideas gladly welcomed before I spend $400 on a new starter motor. Cheers!

I would check the battery terminals and leads, particularly the earth leads from the battery to engine, engine to chassis and see if the connections are sound