General Motors' Vortec engine has powered some of the best cars GM ever made, but it's not without its problems. Which years present the most issues?

The Vortec 4200 inline-6 outperformed its size, and even though it was used in SUVs from GM and Chevrolet, its existence has nearly been forgotten.

The LS and Vortec engines are well-known to be under the hood of GM models, but there are key differences between them. Here's what you need to know.