Why is my ‘low engine power’ light coming on?

John Paul, AAA Northeast's Car Doctor, answers a question from a reader whose Buick LaCrosse loses acceleration while driving.

–Mark Humphrey/AP

What’s causing my 2008 Buick LaCrosse to lose acceleration?

Q. I have a 2008 Buick LaCrosse with 185,000 miles that loses acceleration while driving, resulting in the “low engine power” light coming on. I often have to put the gas pedal down to the floor to get acceleration. One mechanic said this happens when the engine gets hot. Within the last year and a half, I’ve had the evaporation-control canister, fuel-tank pressure sensor, transmission, catalytic converter, and throttle sensor all repaired or replaced. The problem continues. Any idea what the problem is and how to fix it?

A. The “low engine power” light comes on due to an issue with the drive-by-wire system that GM and other vehicle manufactures use. Any system, such as the traction and stability control system, that is intended to reduce engine power can cause the light to come on. As these vehicles age, poor electrical connections can cause intermittent issues. The car’s computer codes should be checked, its sensors should be inspected, and its ground connections should be inspected and cleaned.

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John Paul is AAA Northeast’s Car Doctor. He has over 40 years of experience in the automotive business and is an ASE certified master technician. Email your car question to jpaul@aaanortheast.com.