I have noticed a constant 'hissing' noise under the rear bumper of my '95 525iA. I have also experienced random 'hickups' when I hit the gas or shaking after the first start of the day. I talked to my mechanic (who's got a tech straight off the boat from Deutschland perfectly equipped with accent, I love them) and he said it's probably the fuel pump, my first guess also. I have the Bentley manual and I would like to replace it myself, but I am a novice at automotive repair. I was wondering, has anyone done this repair? Any advice? I am worried about making sure the fuel pressure is correct.