strange power loss 1/2 full tank

[dieselboy]

good job,
bogus seems to of had this concluded from the start!
glad its sorted.

[denisj]

Reading through this thread, had me motivated to do the same cleanup to my tank.
Symptoms were qute alike. Outer temperature being around tennish below zero, car started flawlessly, just tu start loosing power after a mile.
Managed to keep it on the pedal, so it wouldnt stall, it woke up after few minutes and regained normal behaviour.
Next evening I replaced fuel filter, since old one was probably in for years.
I thought the stalling behaviour was produced by overcooled diesel inside fuel filter.
Well, next morning ride was OK, just to repeat the same when returning home afternoon. Temperatures still quite below zero, it started loosing power and every now and then blue smoke bursted from the exhaust.
After few of those clouds, it regained normal behaviour.
Next morning first mile OK, than it stopped.
I could only keep it idling with full throttle at 600rpm with typical 3 cylinder sound. Left it there, tried to run it afternoon, but it was a no go.
Towed it home and pulled the tank off.
Looked inside but there was no slime or jelly like substance inside. Just a few frozenaries from waxed fuel.
Next to do is to blow the delivery and return pipe for possible blockage.

About tank breather filter..is it ok just to blow it or replace it regardless of its state. Seem I can blow and inhale through no matter the side.

There seems to be no fuel pump inside, just delivery and return pipe are lead to the bottom of the tank.

Tank itself is probably the same as on the 2LT

[denisj]

And here's the tank inside look.
Just some flakes on the inner area, where the pipes touch down.

[denisj]

i've cleaned, added warmed fuel with cold weather additive, but it happened again, car stalled.
So, to correct the matter, I took the air compressor and blasted the hose from engine bay toward fuel tank (open filler cap when doing this) and also the tube, that fuel supply hose is connected to and leads through fuel filter to injector pump and back to tank via return line.
And it corrected the problem.

Then, I dsconnected and measured the fuel heater from the fuel filter and it showed zero impendance and also it is not short circuited, what it should be, to produce heat.
Wires, powering the heater, produce voltage after few second, when the car is started.

I'm not sure what the fuel heater relay (RED) in the fuse box is ment for, as mine is missing.
Also what for is the 40 Amp heater. It is not preheater and rear window heater, since those two already exist in the box.