Why does my car shudder at 20-30 mph.

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. Although it's a little sooner than I'd expect at 20-30 miles per hour, I can say that the transmission torque converter engages somewhere near there...usually over 30 miles per hour, but -- maybe lower too on this model, not fully sure. A torque converter that is shuddering on engagement can be showing evidence of fluid break down - the fluid may need changed. Or, the torque converter clutch could be experiencing a problem too. Too hard to tell without hands on inspection with a diagnostic tool. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.