Yesterday, while I was at my dad’s place, he started the engine to see how’s the white smoke situation was. Well, it seemed like the white smoke was gone. We revved the engine and took turns standing at the tail pipe to look at the exhaust. Hmm…we couldn’t see any white smoke (update 23 Dec: we tried again this morning and there was still white smoke when we revved the engine. Maybe it was the strong sunlight that day that made the white smoke difficult to discern. The car has now ran 750km with Certech Gel)
What we saw was a touch of black smoke. Could be the carbon from the tailpipe or perhaps due to a richer mixture (we richened the mixture screw recently when we replaced the old plugs, The plugs showed the engine was running lean).
We will continue to monitor the car and see how things go. My dad has driven slightly more than 400km since the Certech Gel was first added.