How often does a car need a tune-up?

Your car needs regular oil changes, we all know that, but when does it need a tune-up? In older cars, a tune-up was needed every 30,000-45,000 miles. Modern cars don't need a tune-up in a traditional sense,
Tune-up Tune-up time: Set of spark plugs and wires for a V6 engine, an air filter and a spark plug socket with a ratchet.
since there is nothing that can be adjusted and everything is controlled by a computer. In modern cars, a "tune-up" is a major service that includes an oil change, replacement of an engine air filter, spark plugs and possibly a few additional items.

A tune-up is usually recommended if a car starts running poorly (scroll down for symptoms), or when your spark plugs are due for replacement according to the maintenance schedule.

Spark plugs provide an electric spark to initiate combustion in your engine, so if the spark plugs are fouled-up or worn out, your engine won't run properly.
Spark plug inside the engine diagram Spark plug.
There are two types of spark plugs: conventional and long-life (platinum- or iridium-tipped). Conventional spark plugs need to be replaced every 30,000-50,000 miles. Iridium- or platinum-tipped spark plugs can last for 50,000-120,000 miles. We posted several links where you can check the maintenance schedule online in this article.

Worn-out spark plugs can cause misfiring, lack of power and poor fuel economy. Even ignition coils are known to fail if spark plugs are worn-out. Most cars today have ignition coils installed right on top of the spark plugs, without spark plug wires (ignition wires). In cars that do have spark plug wires, they are usually replaced together with spark plugs, unless they are in a very good shape. Spark plug replacement costs $120-$260 in a 4-cylinder car and $160-$600 in a V6 or V8-powered vehicle. Read more: When do spark plugs need to be replaced?
A fuel filter used to be another major part of the tune-up. Thanks to improvements in technology and fuel quality, fuel filter replacement is not required in most modern cars. Again, your maintenance schedule will tell you, when if ever, it needs to be replaced. For example, if you have the 2009 Ford Mustang, you should change its fuel filter every 30,000 miles according to the maintenance schedule. However, there is no mention about the fuel filter in the maintenance schedule of the 2019 Toyota Camry.

Similarly, for the 2017 Honda Accord and 2018 Mazda 3, the fuel filter is not even listed. Nissan in its 2010 Service and Maintenance Guide says that "Fuel Filter is Maintenance-free item (in-tank type filter)." The main symptom of a dirty fuel filter is lack of power on acceleration or when driving up-hill. Replacing a fuel filter, if it's installed outside of the tank, can cost from $90 to $160.

Diesel fuel filter. Diesel cars have a
Diesel Fuel Filter Diesel fuel filter, Volkswagen Jetta TDI.
fuel filter has a water separator. The water separator needs to be drained every 10,000 miles or sooner. Replacement intervals vary. For example, the maintenance schedule for the 2017 Audi model year recommends replacing the diesel fuel filter in TDI models every 20,000 miles.

An air filter is the one item that surely needs to be replaced during a tune-up. The main job of an air filter is to prevent dust and sand from getting inside the engine and damaging cylinder walls. An air filter is recommended to be replaced every 15,000-30,000 miles or sooner if you often drive on unpaved or dusty roads.

When the air filter is extremely dirty, it strains your engine – remember how a vacuum sounds when something clogs it up?
Air Filter Replacing an air filter.
Replacing an air filter is not very expensive ($25-$90) and it's an easy project for any DIY car enthusiast. When you replace an air filter, your engine will "breathe" better. Read more: How often should an air filter be changed?

What else may need to be replaced or adjusted during a tune-up? Often in high-mileage cars, the throttle body may become dirty, with carbon deposits preventing the throttle valve from working properly. This issue might cause rough idle, stalling and your "Check Engine" light might come on as a result.
Dirty Throttle body Dirty throttle body.
Your mechanic may recommend cleaning the throttle body as part of a tune-up. This service may cost $100-$180. Read more: When does a throttle body need to be serviced?

Another often suggested tune-up item is the fuel induction service. To perform this service, a mechanic sprays a special cleaning solution or foam into the intake manifold. The main goal is to clean the carbon deposits on the intake valves and the pistons, which might cause problems in high-mileage engines with direct fuel injection. Manufacturers don't include this type of service in the recommended maintenance. This service is more beneficial for problems in high-mileage engines; if your car is good on gas and runs fine, you won't see much improvement. The price can vary from $90 to $180.

If your battery is getting weaker and it's been a while since you replaced it last time, your mechanic may recommend having it tested. Typically a mechanic will run the test of your battery and charging system and if the battery's capacity is low, he or she might recommend replacing it. Read more: When should a battery be replaced?

If your car suffers from poor gas mileage, your mechanic may suggest replacing a front oxygen sensor (or both in a V6 or V8). An oxygen sensor is one of the main components responsible for the amount of fuel used by the engine. Of course, if your car runs fine and your "Check Engine" light is not on, you don't really need it. Typically an oxygen sensor is not required to be replaced as part of a scheduled maintenance.
If your car has a timing belt, it is also often replaced during a major tune-up. Not all cars have a timing belt; many newer cars use a maintenance-free timing chain instead. If your car has a timing belt, it will be mentioned in the maintenance schedule. Read more: When does the timing belt need to be replaced?

If your drive belt (serpentine belt) hasn't been changed in a while, it could also be recommended to be replaced during a tune-up. A drive belt runs engine accessories and is usually replaced every 40,000-70,000 miles; read more: When should a drive belt be replaced in your car?.
For some cars, a mechanic may recommend valve adjustment, especially if the valves become noisy. This service is rarely done in newer cars, but might be beneficial for some vehicles.
Signs that a car needs a tune-up:
– Engine doesn't start as easily as before
– Running rough, especially when started
– Occasional misfiring, especially in humid weather
– Rough unstable idle, stalling
– Lack of power
– Poor gas mileage
Tip: If you want to do a tune-up, let your mechanic know what concerns (if any) you have with your car, so the tune-up will be tailored to address those concerns.