An engine tune-up replaces spark plugs and worn ignition components, checks filters and belts, and runs a full diagnostic scan to explain a check-engine light, rough idle, or falling fuel economy. San Francisco Auto Repair is open six days a week, Monday through Saturday, 9 AM to 6 PM, for tune-up appointments.
A tune-up isn't one fixed list of parts — it's whatever's causing the engine to run rough, hesitate off the line, or burn more gas than it used to, tracked down with a diagnostic scan before anything gets replaced. Spark plugs and worn ignition components are usually part of it, since a misfire is the single most common reason a tune-up gets booked in the first place.
Belts, filters, and fluid levels get checked at the same visit because they're already exposed once the plugs are out — not because every tune-up needs all of them replaced. If the check-engine light is already on, the scan comes first; a tune-up here isn't a blind swap of parts hoping one of them turns out to be the problem.
What's actually included in a tune-up?
Spark plugs and any worn ignition components come out first. From there it's air and fuel filter condition, drive belt wear, fluid levels, and a full scan for stored and pending codes — assessed against what that specific engine needs, not run down as a fixed checklist regardless of the car in front of us.
A tune-up that turns into a full parts-replacement invoice on a car that only needed plugs isn't a tune-up done well — it's upselling with extra steps.
How do I know it's time for one?
Rough idle, hesitation when you accelerate, a harder-than-usual start, or fuel economy that's crept down over a few months are the usual signs — a check-engine light isn't required. Plenty of cars run rough for weeks before the light actually comes on, because the computer is only tracking a specific set of failure conditions, not general roughness.
We follow the manufacturer's interval in your owner's manual rather than a fixed mileage figure applied to every car that comes through the door, since that interval varies by engine and by how the car's actually been driven.
Will a tune-up fix my check-engine light?
Sometimes — if the code points to a misfire, worn plugs, or an ignition component, yes. If it's something else entirely, like a sensor or a catalytic converter issue, a tune-up won't touch it, and we'll tell you that before doing work that wouldn't fix the actual problem.
How often does my car need a tune-up?
It depends on the engine, not a single number that applies to every car — check your owner's manual for the manufacturer's interval, or call (628) 444-4559 with your VIN and we can look it up for you.