One problem related to engine knocking noise has been reported for the 2008 Kia Motor Optima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Kia Motor Optima based on all problems reported for the 2008 Optima.
My 2008 kia Optima stalls randomly. It does not matter if the car is stationary or in motion. There are times that I start it and it will stall immediately and sometimes it will stall as I am backing out of my parking space. There are also times when I will be driving and it will stall which has nearly caused an accident. The problem does not produce a check engine light and no one has been able to successfully diagnose the problem. The issue that I am experiencing sounds very familiar to the newer Optimas that have recently been recalled. The most recent stalling occurred yesterday, 04/10/2017, and there was a knocking sound along with the stalling out.