My linea has run some 140000km and I am getting black smoke even while driving at 1k to 2k rpm. Checked with the garage and he told it is a engine problem. I am confused below I am getting a good milage of 17-18 in city and 20-22 on highway. What I am confused is I get an error message which says "check glow plugs".... but when I asked the technician he told that the plugs were struck and he will replace it while re-boring the engine. And I had to change the timer belt in the last service but he told me not to do it since it has to be replaced after engine re-boring. I am confused what to do pls advice.