Q: I took your advice and purchased a diagnostic scanner. I’ve been playing with it and trying to make sense of some of the things on the data list. I remember you saying that the “fuel trims” were a ...

Fuel trim data is one of the most powerful yet underused tools in automotive diagnostics. By learning to interpret short-term and long-term fuel trim readings, technicians and DIYers can spot vacuum ...

Question: I took your advice and purchased a diagnostic scanner. I’ve been playing with it and trying to make sense of some of the things on the data list. I remember you saying that the “fuel trims” ...