I have a 99 c240 50k miles saloon. The fuel pump whines when the engine is running....it was replaced....still whines...1st pump put on my brother's car....no whine. Can't be pump...anyone know what this might be? sounds like 'neeeeeeeeeeeeeeeeeeeee'...obviously dissapears on over-run throttle-off.
As a 6 cylinder car, the engine is very quite, which makes the noise very noticable and irritating. car seem to run OK (excellent) apart from this.HELP!