About Us Welcome to L&J Diesel Service Inc. Since 1968, L&J Diesel Inc. has steadily grown in size, customer base and diversity. Our reputation is wide spread as an innovative company of dedicated professionals who can be relied upon for superior craftsmanship, quality product lines and responsive service. L&J Diesel Service Inc. began in Miami with one employee, the founder Luis M. Cueto, and only one test stand. The company moved to Jacksonville in 1974 and grew rapidly, relocating in 1990 to a new specially designed and fully equipped facility. Our growth and diversity is continuing with many employees and more than 10 test stands including a high tech computerized 100 hp EPS 815 Bosch calibration test stand for the most powerful and accurate testing available anywhere. Today, L&J Diesel Inc., is the largest, most diverse and complete, independent diesel shop of its kind in the southeast.