hi there so i dirve a 2000 clk430 and when i am driving at any speeds and i let go of the gas i hear a humming noise from the rear of my car. when i push on the gas it goes away. what could casue this and what should i check for thanks..

Internet WAG:

The fuel pump has an insulator. When the insulator goes bad (due to elements) the pump can get louder in certain circumstances. I'd look at the insulator.

whats an easy way of getting to it as i am sure my fuel pump is in my tank.

what also gets me is if i just the cruise control the noise goes away could that still be caused by the diff or tranny?

The pump isn't in the tank. It's next to the filter and talkes about 10 minutes to unbolt and check (I work slow, so some may say 5 minutes). Photo #1 shows a socket screwdriver being used to remove the plastic cover. Photo #2 shows the filter and pump after the plastic cover has been removed. Note the blue insulator. If yours is ripped up / deteriorated / trashed, that could cause the pump to make noise. So could the clamp if it's not tight.

As long as you're down there, you may want to check the flex discs. Photo #3 shows the rear flex disc (to the left of the fuel filter and pump / above the exhaust). There is a rear disc and a front disc. When they wear out, they can make noise. Those are about $100 per disc.

This is an old thread but I wanted to ask what the mileage the fuel filter is normally changed. Dealer tried to tell me I had to replace mine at 31K.

Filter is suppose to be every 65k or 4-5yrs.