Dadge Caravan

First check the fuel pressure regulator by pulling the vacuum hose at the top. Feel/smell for fuel. If there's any, replace it.

If this is fine, I'd say your engine is burning oil. You can try checking the PCV valve. If it's bad, replace it. If this doesn't help, then oil is either creaping past the valve guides or piston rings. While your motor is off, Oil probably collects in the cylinders then burns off when you start it. Also, during deceleration while engine is trying to warm up (Metal expanding inside engine), it's probably pulling oil then as well.

For the heck of it, check your brake fluid level, brake fluid can be sucked into the combustion chamber too, if the diaphram is fualty. Just a possibility