engine light flash when your symptoms appear? if so its a misfire.
did you use the 09 coil packs? not sure what year car you have.
have you logged fuel trims to see if its a fueling issue?
Good call on the cops, 09 has the revised head, plug design with different length boots and coil connectors. Went to a brown boost vice black iirc. If they are the wrong ones could be bad plug connections.