Common reasons a tune-up could make your car run bad:
* Incorrect parts: Using the wrong spark plugs, air filter, or other components can cause misfires, rough idling, or decreased fuel efficiency.
* Improper installation: If parts aren't installed correctly, they might not function properly, leading to problems.
* Overtightening components: Overtightening bolts can damage parts or prevent them from working correctly.
* Ignoring existing problems: A tune-up won't fix underlying issues like a faulty sensor, clogged fuel injectors, or a failing catalytic converter. These problems might become more noticeable after a tune-up because the engine is running "better" overall.
* Unnecessary tune-up: If your car is already running well, a tune-up may not be necessary and could even potentially cause problems.
Signs a tune-up might have made your car run worse:
* Rough idling: The engine shakes or vibrates excessively at idle.
* Misfires: The engine feels like it's missing or sputtering.
* Decreased fuel efficiency: You're getting worse gas mileage than before.
* Increased emissions: The car emits more smoke or fumes.
* Engine light on: The check engine light illuminates on the dashboard.
What to do if your car runs worse after a tune-up:
* Return to the mechanic: Go back to the mechanic who performed the tune-up and explain the problems you're experiencing. They should be able to diagnose the issue and fix it.
* Get a second opinion: If you're not confident in the mechanic's ability to fix the problem, get a second opinion from another reputable shop.
* Inspect the work: If you're mechanically inclined, you can inspect the work yourself to ensure that everything was done correctly.
It's important to note that not every tune-up will result in a car running worse. A well-done tune-up using the correct parts and procedures is almost always beneficial for your car's performance and longevity. However, if you experience problems after a tune-up, it's important to address them promptly to avoid further damage.
