Hi there, I'm Al the owner of Big As Auto Repair

When a vehicle doesn't coast properly it can be several things that can cause it. There could be a possible brake issue, in other words there could be a caliper sticking and causing the brakes to slow the vehicle down. There could be a transmission issue, trans issue's can cause all sorts of problems and reason why the vehicle will not coast properly. If you know someone that's mechanically inclined that can jack each one of your wheels off the ground and move the wheel by hand and se if it is locking up, if you find one locking up then it could possibly be that caliper sticking are could simply be corrosion build-up where the brake pads slide on the bracket. For further assistance please visit my website and click on "Contact Us" have an awesome day! Auto Repair