rough engine idle and fuel pump noise

Hi to all out there in METRO land. I have a 1997 metro 5 sp w/ the 1ltr engine. The car has 220k miles, but runs ok w/ some issues. It still manages around 50 mpg. I am experiencing a rattling sound from the back of the car. It sounds almost like the exhaust hitting the frame. I had a car repair shop put it on a rack and look at the exhaust. They sd that the exhaust syst. in good shape and that the sound appears to be coming from the fuel pump. When you bring the engine rpm off idle, the sound goes away. The car also has a intermittant rough idle. It only happens when the engine at normal opperating temp and it has to be sitting idling for a few minutes, almost like coming to a long stop light. I replaced the fuel filter which was clogged ( couldn't even blow through it). That didn't help the noisy pump, or idle problem. Next, I dropped the fuel tank, drained and inspected. From what I could see w/ a flashlight, the inside of the tank is pretty clean. I replaced the fuel pump thinking that it may have been on the way out w/ the noise nad rough idle. No help. Still have the same problem. I did notice that when the idle starts to get rough, the timing mark is all over the place when I check the ign. timing. When I shorted out the 4 wire pig tail that the manuel tells you to short out to check ign timing, The idle appeared to smoth out and the timing mark became stable. The timing was a little retarded, at 2 btdc. I set the timing to 5 btdc per the underhood sticker. The car seems a little perkier, but still the same idle and noise problem Do any of you fine people out there have any suggestions. Hopefully somebody has experienced some similiar problems.
Any help would be appreciated.
Chris Neville
[email protected]:screwy: