Thanks for the response. But I am curious of what the clutch has to do with the noise since I am in Neutral gear. But since you mentioned, I also noticed that if I am in 2nr or 3rd gear, foot off gas pedal and let the car glide, it also made the similar noise too sometimes. I haven't serviced the clutch either at this point.

Yeah, I am very surpised at the amount of oil I am burning too but I only saw the blue tint of smoke when the engine was cold, like warming up in the cold morning. Otherwise, I hardly noticed it. But the power is definitely a big concern to me. I tried Esso Supreme Octane 91 (bad performance), PetroCanada Octane 91 (ok performance) and Octane 94 (which makes me feel like what the car was like when I bought it). I haven't tried Chevron yet. I also used Pennzoil injection cleaner once and it seemed to help a bit afterward but it was only a minor differnece. I used Mobil 1 synthetic 5W30 oil once and it seemed to slow down the burning a bit (probably 800-1000km or so to burn a litre). My mechanic also put a litre of the really thick oil from STP in it once too but it didn't help much.

Maybe I'll try your suggestion and switch to 10W30 on my next oil change. I have been using Pennzoil everytime on this car, should I switch it to another brand? In my old Prelude (4th Gen SR), I always used the Castrol Syntec 5W50.