When do you change an egr valve on a 2005 Chevy Malibu?

You should replace the EGR valve on a 2005 Chevy Malibu when it's malfunctioning and causing problems. There's no set mileage or time interval for replacement; it depends on the condition of the valve and how well the car is maintained.

Signs you need a new EGR valve include:

* Check Engine Light (CEL): This is the most common indicator. The code will usually specify a problem with the EGR system.

* Rough idle: The engine may idle roughly or stall.

* Loss of power: The engine may lack power or hesitate during acceleration.

* Poor fuel economy: You may notice a decrease in gas mileage.

* Excessive smoke: Black or bluish exhaust smoke might be present.

* Backfiring: In some cases, a faulty EGR valve can contribute to backfiring.

Important Note: Simply because the check engine light is on doesn't automatically mean the EGR valve needs replacing. The code needs to be diagnosed properly to pinpoint the exact cause. A mechanic can use a scan tool to read the diagnostic trouble codes (DTCs) and determine if the EGR valve itself is at fault or if another component in the EGR system is the problem. Replacing the valve without proper diagnosis could be a waste of money if the problem lies elsewhere.