KIA SORENTO ENGINE HARD TO START

What Could Be Causing A Hard Start And White Fume From The Exhaust On A Kia Sorento Suv

Changed The Maf Sensor For A Second Hand One And Still Hard To Start. After Starting It A Couple Of Times It Cranks And Started Quicker....

Wouldn't Crank At All So Changed Starter Then Started With A Little Gas Pedal Pumping. Drove A Bit Next Start It Revved Hi For A Few...