1,243 problems have been reported for the 2004 Chevrolet Impala. The following chart shows the 25 most common problems for 2004 Chevrolet Impala. The number one most common problem is related to the vehicle's electrical system with 654 problems. The second most common problem is related to the vehicle's engine and engine cooling (99 problems).
In our research we use the PPMY index to compare the reliability of vehicles. The PPMY index of a certain model is defined as the problems reported per thousand vehicles per Year. The total sales of the 2004 Chevrolet Impala in the United States are 279,789 units [1]. If the total number of problems reported by Chevrolet Impala owners in the last 21 years is 1243, and the age of the vehicle is 21, the PPMY index can then be calculated as
PPMY Index = 1243 / 279,789 / 21 * 1000 = 0.21.
For more information, refer to this page: A study of reliability comparison across Chevrolet Impala model year vehicles.
The following chart shows the number of problems reported during each of the service years since the debut of the 2004 Chevrolet Impala in 2004.
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When making the decision between buying a new or used Chevrolet Impala, the following table can be used to compare the 2004 Chevrolet Impala with the Chevrolet Impala from other model years. Note that the number of problems reported for the 2004 Impala is 1,243 while the average number of problems reported for the 25 model years of the Chevrolet Impala is 551.