UTC San Diego

I'm sorry that I didn't see the rule that I cannot ask the similar questions on the different post. I appreciate those fellow members who gave me advises and comments regarding to my car problem.

It sounds like cheap electric motor is running when I step the gas pedal. My engine check light is on and off sometime. There's no vibration except the engine runs like beating a rhythm (normally engine sounds consistant). How can I explain.. Sounds like rev up and down, up and down..

It starts few weeks ago, the motor like sound came from under the hood when I step the gas pedal. Also, engine doesn't idle smooth but idle like a beat. I may over fill the oil, but is that the cause?

I just drove the car this evening and the sound came from front almost like from behind the main panel. Also, the engine idle sound not smooth now. RPM is stable but engine sounds like "Bbb...Bbb...Bbb...Bbb..." BTW, what if I don't replace the heat shield or air filter? What would happen to the car?

Actually there're no vibration. Just metal kindda squeaky noise like "zzzzzzzzz". I think I heard the noise from passenger side. Thank you for your comments.

It may be a small metalic kindda noise. The noise itself is not that loud. My Lexus was fairly quiet before this, and I noticed this noise when I idle or start the car in last few days. My area was raining hard for last few weeks and I just wonder if that has something to do with it. Maybe not.

I heard buzz noise like "zzzzzzz" from front when I step on gas pedal to go from stop. Mine is 91 LS400 w/ very high mileage. What could it be? I appreciate any comment or advise. Thanks!