that doesnt sound the same mate,it just lowers the rev limit really to 4k,the car still drives fine till it hit 4k mark,just been out in mine again and i start it from cold allow it to warn try to rev it to max and it goes to 4k----turn it off then on almost straight away and its fine up to propper rev limit and driving as it should good luck mate,i had a simlar proplem as that popping banging and black smoking a few years back and that turned out to be the coolant temp sensor playing up