Off the top of my head, episodes where cars play a big role and are not just incidental to an episode. Anymore?
1. Can't find car in parking garage 2. George in parking space dispute with bald guy 3. Mechanic steals Jerry's car; tailed by Kramer and Newman in the postal van 4. Jerry's car has bad BO 5. Elaine's a bad driver 6. Gang parks in handicap spot 7. Jerry buys new car from Puddy at dealership; Kramer goes for test drive 8. Jerry and Kramer distracted by woman wearing bra, leading to accident 9. Mental patient lands on George's car 10. "Bad boy" George borrows Dad's GTO to impress girl 11. Jerry and George take limo ride with Nazis 12. "White Whale" Newman is scofflaw who evades parking tickets 13. Kramer puts blood is Jerry's radiator 14. George supposedly buys Jon Voigt's car 15. Kramer drives to California but car breaks down; catches lift in van 16. Car rental company loses Jerry's reservation; George gets into accident with Jerry's rental 17. Jerry buys Dad a Cadillac 18. Jerry buys Dad a second Cadillac, but Jack Klompus ruins it 19. Kramer adopts a highway and widens the lanes; Newman's postal van catches fire 20. Prostitutes are turning tricks in George's car 21. Puffy refuses to work on Jerry car's after Jerry accuses him of stealing his "move" 22. Jerry wins a free van 23. Jerry and the gang get stuck in Puerto Rican Day traffic jam 24. George drives over squirrel 25. Bald guy trapped in Jerry's trunk 26. Mental patient fiddles with George's engine, which catches on fire in front of Monk's restaurant