Car trouble · Engine & check-engine light

My car is getting worse gas mileage

You are filling up more often than you used to for the same driving. A few simple things are worth checking first.

Not urgent

A starting point, not a diagnosis. Most parts stores read check-engine codes and test batteries for free.

Likely causes — tick the parts you want

  1. Low tire pressure

    most likely · Most people can do this

    How to check: Check all four tires with a gauge when the car has sat a while, and compare with the sticker inside the driver’s door jamb.

  2. Worn spark plugs or a failing oxygen sensor

    possible · Doable with tools and a free afternoon

    How to check: If the check-engine light is on or the engine feels less smooth, have the code read. Old plugs and a lazy oxygen sensor both waste fuel.

  3. A very dirty engine air filter

    possible · Most people can do this

    How to check: Open the air filter box and hold the filter up to a light. If you can barely see light through it, it is due.

  4. A dragging brake

    less likely · A mechanic’s job

    How to check: After a drive, carefully hold your hand near each wheel without touching it. A wheel much hotter than the rest means a brake is dragging.

Your car — the counter needs this

If the counter doesn’t have a part, your shopper asks them to order it under your name and messages you the order number. When it comes in, send someone to collect it.

Not quite it?

My check engine light is flashingMy check engine light is onMy oil light is onMy engine idles rough or shakesMy car hesitates when I accelerateI smell burning oil
My car is getting worse gas mileage — likely causes and the parts · DriverRuns