I recently purchased (several months ago) a 1990 240 DL Wagon. I fell in love with the car. I have been replacing the stuff that normally goes out after 175,000 miles. I was letting the car idle after I had driven it a few miles (about 10) and I heard a really strange sound coming from the main fuel pump. It sounded like a high pitched electric razor. I turned the car off and let it cool down a while. I started it back up and no "strange" sound at all. I then listened inside the fuel tank and heard the intank pump running just fine. I then drove the car to the grocery store (about five miles) got out with the engine running and heard the sound again. After I got home, the "electric razor" sound was still there, so I grabbed a small funnel, stuck it into the Gas tank hole and listened for the intank pump. All I heard was Ocean Wave type sounds. My question, I have deduced that the intank pump is probably going bad. Secondly, I am a pretty good D.I.Y. Mechanic and wondering if I am on the right track in my deduction, how difficult is it to replace after you get the "bung nut" loosened? I am only afraid of causing a gigantic explosion in my neighborhood with me inside the car. :-()

Any and ALL help would be greatly appreciated. Like I said, the car has 175,000 miles on it. It just started making this sound yesterday (Saturday, January 25th).

Thanks in advance.

Todd :-)