Volkswagen Repair: 1983 VW Jetta, vw jetta, mechanical fuel injection

Question
I have a 1983 Jetta that lost power on highway, I shifted down to 4th (manual) and drove at 80 km/h (45mph) for a while. Lost power again, then had to shift down to 3rd, ran alright in 3rd, went back to 4th, lost power again, down to 3rd etc. car stalled, and would not start for 10 minutes. Got it running and up to fifth gear 60 mph for 5 miles then same thing over again, until 3rd gear at 30 mph or so. Got the car home and into the shop to have a mechanically inclined friend have a look. He hasn't worked with Mechanical fuel injection, but knew to check vacumn leaks etc, no pressure tester...
 The car will start and idle up for maybe 3 - 5 seconds, then dies. Give it foot feed, it dies. Do nothing, it dies. That is all it will do now.
 I took out the rear seat and removed sending unit cover (everything looked good, gasket was good). I was told possibly the screen in gas tank collapsed, there is no screen up there, and I don't know if there should be or not. I don't have a fuel pressure tester, but I know there is fuel coming from the injectors, as we had injector out and fuel sprayed out injector. Noticed injector o-ring is rock hard, can't find any the same ones to test that as a solution(I live in south western Saskatchewan Canada, not much for vw dealers or help too close) I really don't know what else to tell you.
 - checked for vacumn leaks
 - there is fuel pressure, not sure how much...
 - Are there any simple things to try before ordering all these expensive parts like fuel pump or cold start valve or fuel accumulator, etc. only to install them and end up right where I am with a broken vw requiring only a quick ground wire tightening or something easy?

All of this just happened out of the blue one day. The car ran great up til then. Only 100,000 miles on it very solid car(no rust, like new). I want to drive it again.
Thanks in advance for any help.
Brody

Answer
Hi Brody;
This definitely sounds like a fuel issue.  And, unfortunately, for you, and your mechanically inclined friend, it sounds like a fuel pressure issue.  To ensure that you do not spend huge money on a bunch of parts that may leave you stranded anyway....invest a little into a fuel pressure tester.  Look for used stuff.  Look for garage sales with tools.  No matter how you slice it, though.  You will have to know what the fuel pressure is, just to narrow down the possibilities.  There is big difference from having pressure enough to make an injector operate at atmospheric pressure, out of the car, and the conditions inside the cylinder head, when the intake valve opens, there's a BIG difference.  Anyway, it almost sounds like not enough pressure, so fuel pump first, but check the pressure before doing something I think MIGHT work from 3500 miles away.  Good luck Brody.