CharlesY

I have a 2005 E350 which recently giving out some high pitch whizzy noise everytime when the gas pedal is pressed. Its sounds like a cat meow or sort of high pitch whistle which I still don't have an idea the cause of the annoying sound and I hope that its nothing major. The sound is less obvious when the engine is idle. I also check the pipes out but there are no obvious cracks etc.

Today I took out the engine air filters and clean them thoroughly but with no avail. I suspect the noise could come from one of the following (please advise) I wonder if any owners here have experienced similar problem and what is teh fix:

1. the alternator is failing
2. the fuel pump is failing
3. the oil pump is failing
4. the water pump is failing
5. or something else

My last resort is to take it back to a MB garage to check out.