Originally published 2/5/2020. Learn how DEF usage can be a diagnostic tool.

How an engine starts is a diagnostic clue.

The valve seat determines low lift air flow.

Originally published 1/29/2020 Ray Bohacz lays out a plan for success.

Special care is required when working with sensor circuits.

What can be gleaned from the odor of the exhaust.

Originally published 1/22/2020. A poor ground circuit may be eating your engine and profits.

Three simple things that make a big difference.

We need to examine where we came from to know where we are.

Originally published 1/15/2020. 15 common mistakes mechanics make that will affect the quality of repair.