2005 Sunfire Knocking sound whenever not on smooth roads engine runs great manual transmission shifts good also 100% sure it's not the engine on smooth roads there's no noise at all on uneven rough roads usually at speeds 40 and below the slower im driving the louder the Knocking sound is rpms are stable not throttle related cars getting over 30mpg is this probably something the suspension? I'm hoping for a simple not too crazy expensive fix literally just got the car thank your for your help!