Most likely, when you talk about a tune-up or using the Engine Diagnosticcs equipment, its probably because you’re experiencing some kind of driveability problem. Your vehicle might be getting hard to start, not getting the fuel mileage it once did, hesitating or stalling, knocking or not running with the same zip and power as before. Or, your vehicle may have failed an emissions test. So what you probably need is an engine performance analysis — and maybe a new set of spark plugs, too.
A simple maintenance type tune-up (a new set of plugs) may make an engine easier to start, improve fuel economy, lower emissions, restore lost pep and power, and so on provided engine performance deteriorated because of worn or fouled spark plugs. But if the problem lies elsewhere, the Engine Diagnostic check will identify what is causing the issues.
