I would start with a tune up: new plugs, air filter, oil and oil filter. You can then see the color of the plugs and maybe discover more on what is going on. Is the smoke there on every start, cold or hot?
JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
KYB Gas-a-Just shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.