Thanks to all of you for proper guidance. I finally got all the issues solved. The oxygen sensor was out of order so it was to be replaced with a good one. Catalytic converter needed cleaning, so it was cleaned. Job done!
Now, my concern is my car's tyres, which are well-used Japanese tyres named "ANASAVE" with the size 175/70/14. I keep normal air-pressure in tyres, wheel alignment and wheel balancing are also OK BUT... they lack comfort on bumpy roads. My car's shock-absorbers and springs are OK. Tyres are a bit different than the car's recommended size which is 185/60/15. The local tyre-seller asks me not to replace them with the recommended size, as it will not make any big difference and it costs a lot too. Besides, mine don't have the word "P" that stands for "Passenger". Does it mean my car's tyres are not for cars, and perhaps they are for light truck? and perhaps that's why they make me feel hard. Kindly suggest a solution if possible. Thanks.
