Just an Idea: Fuel line cleaner
 

When cleaning a fuel system I suppose on any vehicle, would it be a good idea, after cleaning the tank and changing the filter to attach a small rifle brush to a cable and run it through the main hard fuel lines? bypassing any of the usual obstructions, like joint connections and check valves and other. I feel this would be a step a cleaner fuel system, as opposed to just blowing it out with compressed air.

I'm not sure if that's needed if your running fi cleaner. The fuel is running through there under high pressure. It should blast anything on the inside clean.

I'm sure a good scrub wouldn't hurt...for the mind at least :)

I did this on a 123 240D once. It was easy, knocked out some dirt, and did give me a bit of peace of mind. I don't remember the cal. of the brush, but I think I used a .303.

I decided to do this after buying the car and changing the filters. They were dirty, so I decided to clean the strainer in the tank and it was even more clogged up.

But on a gas car the fuel line cleaner ought to get most everything. On my old 6.3 the owners manual said to remove the fuel lines from the mechanical FI unit and blow them out with air at no less than 600 psi. That may have been a misprint, but no matter. I just hit it now and then with some Techtron and never had a problem with it.

If the line is so badly plugged it needs cleaning,i would expect the tank and fuel feed pump on injected engines would need doing too.
The best way to clean old lines on cars that have sat is to connect a cleaning gun with toluene on the front end and blow back towards the tank with a hose leading to a catch tank. I have a machine here called a carbaclean,which pumps a fluid through the system to do the same job.