I have a Honda civic exi 2006. I have been facing problem since last two years that when I start my car in cold condition its engine misses and black or rich exhaust produces and rpm of engine become quite low which causes the engine vibrate and if you put it in gear it stops, but as the engine becomes almost full warm this problem mostly eliminates but still minor roughness in engine running is being felt. When this problem further increases I take it to workshop where mechanic takes out the throttle body and washes it with carburetor cleaner and then problem of missing engine and black smoke resolves completely. But after one or two months the same problem reappears. I also got its engine tuned many times from general workshops but this problem reoccurs again and again after two or three months. Please advice me what should I do and what is the root cause of this problem. Is this due to faulty throttle body or something else. Please do answer my question and I shall be obliged. Thanks. Khawaja Jodat Wapda Town Lahore. 03008457344