One problem related to engine grinding noise has been reported for the 2012 Chevrolet Impala. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Chevrolet Impala based on all problems reported for the 2012 Impala.
Accelerator response time takes too long to re-accelerate . After letting off gas then re-applying pedal while driving, response time should be 800 mili seconds for an electronic accelerator but , it is way longer and makes car backfire at times if I hold pedal after the lag in response . This causes car to lunge and could cause me to get rear ended or damage engine. Second, rubbing grinding noise (not loud) from right front and more noticeable while traveling at 35-40 mph around a left bend in road or by moving steering wheel to left about an inch while driving straight down road. Dealer claimed no problem found on either issue , although they claimed to have replaced a strut bearing on right front. There must have been a previous issue judging by the worn tire before I purchased car. I figured it was an alignment problem that may have been fixed because car didnt pull to one side and drove straight , but apparently there is still an issue and noise is slowly getting more noticeable unless I'm just tuned into it.