Fuel Pump Noise?

Car is an '89 Mercury Cougar. It has been in the family since new. 76,000 original miles. Runs and drives great.

About 2 weeks ago the fuel pump steady "hum" changed to an irregular sound - sort of a "gargle" type of noise. Car still runs fine. To be safe, yesterday I replaced the fuel filter to make sure it wasn't restricted - making the pump work harder than normal. Nothing changed.

My question is... does this new noise characteristic mean anything at all? I know fuel pumps can sometimes make noise for years and keep running just fine. I just thought I'd check here to see if anyone has had any experience with the Ford pumps. And if I end up replacing it, are there brands to avoid? Are the NAPA pumps ok?

Thanks..

Napa pumps are alright, but you can get an pump of equal quality somewhere else cheaper. I wouldn't worry about the noise just yet, when the pump goes it goes.