my car is missing both on petrol n cng..its daewoo racer...i recently changed its ecm as it was faulty but before changing it,it was just missing on cng n dat too just on startup n then car would go smooth but now after just changing the ecm with the right one car started missing...the mechanic ran it on diagnostic mode n it started missing....the plug wires been cleaned a month back n i dnt know any reason for them to b shorted all of a sudden..can anybody help me out