Car bluetooth is often very flaky. If its an oem radio sometimes the dealer can update the firmware on newer vehicles to fix bugs. Many, many people have problems connecting to their different cars because each implementation is different. Try these and see if it helps with the disconnects.
History: Treo 600, Treo 650, Treo 700, HTC Titan, HTC Diamond, Nexus One, SGS1 (Captivate), Samsung Infuse, Galaxy Note, ATT Galaxy Note 2, T-Mobile Galaxy Note 3
Tablets: Nexus 7 2013 LTE, 2x Nook HD CM11, Nook HD+ CM11, Samsung Galaxy Tab 2 LTE, Asus MeMo Pad FHD 10 LTE