Originally Posted by VA-Merc

Thanks for the quick replies! It was a new (and not used) pump I bought off of ebay. It does not make a bubbling kind of noise...more like an electric motor whine (similar to when you have a noisy electric fuel pump on a gas powered car). You are right though, I should double check the mounting. I did put it back in the rubber-insulated mounting sleeve, but maybe it is sitting a little too close to the firewall. It still seems odd to me that it sounds like it is speeding up and slowing down. Would a good check for the ccu control be to put a voltmeter on the pins in the plug while the pump is running and see if it is getting a constant 12 volts? I guess I can't rule out a faulty new pump...I just wasn't sure if it was normal for these...I had thought they were either completely on or completely off.