Hi guys,

I'm supposed to put this to fuel talk thread but i'm not yet sure.

-engine knock started after my third fill-up of petron unleaded. I used the fuel since the car arrived and because it's the closest proximity to my place.

-engine knock is very faint and usually happens at low speed 0-30 kph.

-engine knock happens when engine is already at normal temp. (hot) and when you feather the gas pedal (light press)

-engine knock is at worse when under heavy load, uphill or doing a sharp turn.


asked for advise from the experts and here are the things i tried first

1. tried a higher octane gas (XCS), still the knock persist.
2. tried BLAZE 100 - knocking seems to stop but fuel is so expensive and engine seems to be unusually erratic when starting in the morning (cold start)

-i went to hyundai casa to have it checked.
-casa was not able to find the problem but insisted there is something wrong with the fuel since the spark plugs are unusually corroded and moist.
-casa suggested to replace the spark plugs and fill-up the tank with SHELL unleaded.

CURRENT STATUS:

-filled up with SHELL unleaded (it's my third fill)
-i'm not sure what's with shell unleaded but knocking sound is almost none existent now but still manifest from time to time specially when conditions are right (stated above)
-still waiting for the arrival of the spark plugs.
-for the record, the cvvt engine is a little noisy in the morning, makes me feel i have a small diesel engine, but it becomes lesser as the engine becomes hotter. (is this normal?)

-I will keep you guys posted.
-Any feedback/comments will be highly appreciated.