Bhai jaan first tell me is your car is on CNG, if yes then u donot drive because missing will become more and most of the CNG cars missing due to valve problem, because in CNG cars engine produce more heat and valve make more compression to pistons, if you car is more than 1,75,000 km then overhaul your engine thats it otherwise you have to spend more on pistons, which is costly. When overhauling just put, tappet rings, pistons rings, valves from FUJi or Toyota Genuine, with a mark of toyota on valve. It will cost u around 14 to 16 thousand.