i have a 99 civic si and when i started my car, the motor all of a sudden idle kinda rough. then when i put it in first and drove off, the motor felt like something was holding it back like it was bogging until i reach 3k rpm. then a check CEL came on and instead of staying on, it was BLINKING. i never seen that happen before but when it stayed on i check what was the CEL code, the code was 80 which is exhaust gas recirculation. now can someone please explain to me wat is exhuast gas recirculation? and wat could be the problem?