Especially, if you ran extremely low on fuel, the pump can pick up and pass small rust and scale but the filter will catch all of it and block your fuel supply. Be extremely careful if you remove the filter because of pressure between the pump check and possible filter blockage!
TIP: Use long needle nose vice grips and small protective wood blocks to "pinch" the fuel line supply. Don't over do it! You can damage the line if crunched too much. Allow a little fuel to drain into a can from your control point to prevent any sediment from entering your new filter. Don't be smoking or do this work around any open flame! We want you here next Christmas too! Happy Holidays.

Jr
'89 535iA

If your check engine light came on, and you have a Bentley manual, then check the code...it should probably indicate an oxygen sensor code, which indicates (potentially) that your car is in fuel starvation and running lean due to your fuel delivery problem. Don't sweat it, just check the fuel pressure at any local repair shop that deals with imports (you need a guage).
If the pressure's low, start with the filter!!! Don't get bamboozled into a new pump until the filter is replaced and the old one is inspected for blockage.

My first thought is a bad fuel pump. If you can, try and test the pressure of the fuel system.

My '91 535i won't run. Here's the story.

It will fire up, but runs extremely rough (no more than 500 rpms) and I have to push the gas pedal about halfway down. Then it will die after sevral seconds.

Several days ago, it started to get a little rough on start up, but would smooth right out. Then yesterday, it took it a couple min to smooth out.

Today it took about 10 min. Then I filled up the gas tank (I ran in pretty low). It ran fine for about 50 min, then started running rough again for the final 10 min of my trip. During this final 10 min, the check engine light started to flash. This was the first time I've seen the light, and it only flashed (not constantly), it didn't stay on. I let it sit all day, and then it wouldn't run. It does what I dsecribed above.

First things that come to mind are O2 sensor, fuel filter, bad gas, or (I sure hope not!) injectors. Do any of you experts have any suggestions? Any thing I should immediately look for or tests to perform? It is a '91 535i with 110,000 miles.

Thanks, and Happy Holidays.