Thanks everyone.
I guess the culprit is the thicker oil which i have used i.e. 10W40, shell helix HX-7, car vibarting a bit more and as far as i can understand due to thicker oil initial pick is not as good as it should be. Before today, i didn't know much about oil classification, but this site www.bobistheoilguy.com was really helpful. After gaining some information over the internet, i have come to know, 10W40 is a thicker oil. Thicker oil is more suitable to older cars where oil level goes down during driving. The shopkeeper didn't inform me this and i was stupid enough to buy it blindly I guess the 10W30 or 5w20 could be good for vtec. Lighter oil means less work for engine, hence a quieter engine. Now this thicker oil in my car needs to be flushed.
If you guys have any experience which oil is the best for vtec-cvt, please do share.
@ Retrograde
I have CNG in my ride but hardly used it after 36k, and in 36k only 60% is on CNG. Also I am thinking to get rid of CNG, very likely that it is going to be uninstalled.
@ RL589
iridium plugs were installed at 35k and now car is at 46k.
btw, which plugs you have in your car ? how you feel that response is improved?
Also here is lengthy but very good article about vtec steermatic (Vtec/Jazz). Tell you pros & cons of steermatic ride.
http://asia.vtec.net/Reviews/JazzVtec/index.html
they somehow suggest this oil
http://asia.vtec.net/advertisers/Torco/index.html