I have daihatsu terios 1997. I serviced it ,changed oil,oil filter air filter, and spark plug.the first time i cranked it the engine after servicing it started but it is vibrating while on idle.So when the engine stalled and try to crank again there is bit of firing. Put back in the old plugs and still have the same problem will just start but very running rough.Checked the new plugs 2 are firing ok 2 are black in the same sequence 1 ok 2 black 3 ok 4 black. Read on justanswer a guy had same problem but i don't know how he fixed it. going to reset the ECU tomorrow good night from Aus.