Thanks guys, info really helpful, just hope nothing bengkok, cause it sounded expensive anyway This is the problem, I've used Full syn all the time i had the Car, bout 5 years, my previous service i changed to semi-syn, then back to fully-syn, foolish I know. The Sound goes off when I rev the engine, when i leave the pedal and let it go back to idel, there is no sound for about 1 minute, then it comes back again. initially I thought it was also the injectors, but there is no drop in performance. I could be wrong. Probably the cheapeast step is to change to a higher viscosity oil, and see what happens. Next will also check injectors, just to be sure.
However any idea how much the hydraulic lifters would cost?
Another thot, anybody thinks that fuel pumps may cause this. I think my fuel pump has been acting up. Sometimes difficult to start after one day of not driving, have to pump accelerator until able to start. Battery is ok. Appreciate any help on this