One problem related to gas recirculation valve (egr valve) has been reported for the 2007 Chevrolet Impala. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2007 Chevrolet Impala based on all problems reported for the 2007 Impala.
Engine power was reduced while I was traveling with the flow of traffic. I attempted to accelerate but car started slowing down. Took the vehicle for repair and replaced the pedal position sensor was replaced. I contacted chevy dealership service dept and was told it's a common occurrence. Impalas have a throttle sensor instead of cable. If the sensor goes out, the engine power is reduced to protect the engine integrity. In some cases, it's reduced significantly. The manufacture noted my concern but the rep would not escalate the matter. I went online to file a complaint and there is a chevy forum with similar concerns. General motor reps reply with common responses to take the vehicle to an authorized mechanic and their concern has been noted. I was informed by representative at 800# for manufacture to call back if it happens again. Thankfully I wasn't going at a higher speed in dallas traffic. Not sure if I would have had the luxury of pulling over.