Which parts fail
Components named in complaints (accelerator pedal, throttle, sudden acceleration, cruise control).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2003 Chevrolet Impala owners, lightly cleaned up (personal details are redacted by NHTSA).
Traveling at 58 mph in Cruise Control for 10 minutes I increased speed with 4-6 rapid pushes of the Accelerate button in less than 1.5 seconds, Each push is 1 mph. I have never pushed it that rapidly.The engine acted as if I floored the accelerator & the transmission went from 4th to 3rd gear, speed went to 70+ and rapidly increasing. I stepped on the break pedal several times to disable CC but no help, I switched the CC button to the off position several times, no help. Now at 85+ and accelerating hard in wide open throttle (WOT). I shift to Neutral and turned the ignition to the ACC position to retain steering ability as the engine was RPM'ing out to destruction. I coasted off the highway and set ignition to off. After a few minutes I turned engine on and it rev'd out of control, still WOT. Ignition off did not reset the problem. …
There are 3 recalls I have found that possibly are effecting my 2003 Impala but because my specific VIN # doesn't fall under any of these GM is refusing to fix these problems. 1)the body control module needs to be reset. Apparently when it goes out the cruise control disengages.....and my cruise control light is on but won't engage. Plus my mechanic says the body control module also is what is could be causing my heater fan to not work nor my information display to work. But low and behold when the cruise control light goes off they both work 2) there is a recall stating drops of engine oil May leak on exhaust manifold with hard braking and I sometimes smell oil burning after I drive. …
I was traveling on a 2 lane road. A truck pulling an enclosed trailer was in front of me turned on his right blinker and began to brake to make the turn. I was traveling 77 MPH, so I moved to the oncoming traffic lane (the left lane) in order to pass the truck. At the last second the truck swerved into the left lane in order to make a wide turn. I abruptly jerked the steering wheel right to avoid collision with the truck, but the vehicle seemed to lose power steering as well as power brakes. I was unable to straighten the steering wheel back after jerking it to the right to go back into the right lane; my vehicle hit the back of the enclosed trailer and then hit steep ditch where my back passenger tire popped and the vehicle flipped onto its roof. The vehicles airbags failed to deploy even though the vehicle has significant damage to the front , top and sides of it. …
Tl* the contact owns a 2003 Chevrolet Impala. The contact stated the vehicle increased speed violently once the brake pedal was released. The accelerator pedal was not depressed. The contact pulled over, shut the ignition off and restarted the vehicle, but the failure persisted. The failure recurred numerous times. The contact was a mechanic and stated that the throttle position sensor needed to be replaced. The vehicle was repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 139,000. Updated 1/12/16
ABS, traction, and break lights come on........ Then when I push on the gas paddle its often like the brakes want to lock up , with a scrubbing sound.... Also when I push the break paddle down it often makes a sound and the break paddle feels like it comes back up with the break still down,.........but then when I drive like 20-25 miles the lights go off and hardly come on until I stop again
Tl* the contact owns a 2003 Chevrolet Impala. When applying pressure to the accelerator pedal at 30 MPH, the vehicle would not decelerate. As a consequence he crashed into the wall of a nearby building. He injured his lower body and torso. The vehicle has not been diagnosed by the dealership. The current and failure mileages were 58000.
Whilst driving down the roadway the throttle body became stuck in the open position causing the vehicle to increase speed without the driver being in control of the vehicle which could result in a serious accident with other vehicles on the roadway
I have a 2003 Chevrolet Impala with a 3.8 liter v-6. The car radio quit working and I had to pull out the fuse because it was sending strange error messages to the body control module. Now the BCM is having even more problems. The car turned itself of then back on while I was driving down the road. I pulled over and shut the car off. Then it would not start again. I pulled the fuse for the BCM an the car started and I made it home. What in the world did general motors do to these cars. I have been reading numerous horror stories about their cars. Was there a recall to fix this problem or do I have to go to the dealer and spend a fortune to fix this garbage pretending to be a car. How can a car company get away with this poor quality control in this day and age? My security display now shows random errors like low fuel even after I filled up the tank. …
Engine accelerates to 3,000 RPM during warm up (sometimes). Usually occurs about five minutes after cold start. Has lasted 10 to 15 minutes while driving. Has not repeated during same day and not happen again for days or weeks during the past five months. Replaced ECM (computer), iac (idle air control), coolant temp. Sensor and cleaned throttle body. Dealer cannot suggest solution. Unable to get car to dealer while problem is happening. Scanned for dtcs multiple times, none. Controlling speed with brake is not a good solution. Safety hazard! The consumer stated when the body control module failed, the key fob would not work, the engine would not start, the interior lights would not come on and the head light would not turn off. The consumer had to disconnect the battery, in order to turn the head lights off. After reconnecting the battery, everything returned to normal. …
When I am driving down any road, stopped and turning the ABS system engages causing grinding noise. Loss of power and periodically brakes lock up and gas pedal locks. When pulling off from a stop I can not accelerate & RPM goes almost red line, car starts to jerk and and transmission doesn't shift. I have to let off gas pedal and allow to shift. It has stalled numorus times when pulling into traffic and almost caused me to be hit. The service traction control/ABS warning light dings and stays lit. I manually turn off ABS but problem still occurs. Also the wiring thru out the car has failed to my rearview mirror, domelights and radio panel. My gas mileage has significantly decreased. The problem started around the beginning of the year and has progressively gotten worse to the point I and scared to drive my car.
Acceleration complaints in other Impala years
Frequently asked questions
How common are acceleration problems on the 2003 Chevrolet Impala?
NHTSA has 23 complaints about the speed control & acceleration of the 2003 Chevrolet Impala, 3% of the model year's 695 complaints. The component named most often is cruise control (3 mentions).
Is there a recall for 2003 Chevrolet Impala acceleration problems?
No. NHTSA lists no speed control & acceleration recall for the 2003 Chevrolet Impala, though it has 5 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2003 Chevrolet Impala acceleration problems start?
Half of the complaints with a recorded mileage happened before about 98,000 miles.
Is it dangerous?
Owners linked 3 crashes, 0 fires and 2 injuries to speed control & acceleration problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.