I'm running out of idea here and looking for help.

I'm loosing fuel pressure. If I let the car sit for a while, when I start the car I have 3.5psi. and after 20 minutes it's close to 0.

I've cleaned the tank last week and treated with por-15 gas tank treatment. Same issue. Changed the fuel pressure regulator to a holley FPR and still the same thing. Swapped out fuel pressure gauges still same thing. BTW i checked the tank last night and it was clear of debris.

Could a fuel pump do this???

I'm running a bendix fuel pump (might be at the end of it's life?). It seems like something it clogging up somewhere and now it's clogged pretty good as i couldn't get back to the office after a spirited lunch drive... I'll let it sit for an couple of hours and we will see.

I cleaned the tank thinking if was full of rust. It wasn't that. I did find the fuel strainer in parts next to the 'pickup' in the bottom of the tank. Seems like it wasn't that either.

Oh btw, I'm setup this way:

tank / fuel hose / filter / hose / pump / hose / filter / FPR / gauge / carbs.

Weak link. You've checked everything else. Carbs. Don't know much about them, but it seems they're the only thing that you haven't straightened. Gumout?

Just went to the car and got it to behave. It's now secured in the parking at the office.

I've checked the fuel filter before the pump. it does have particules in it and one is petty big. the one in the engine compartement before the FPR is clean. The more i think about it i'm guessing that the suspect is the hose between my tank and the fuel pump (fuel pump is in the front trunk.) Stainer broke in the tank, and traces of particules in the fuel filter were found... Hose going from the tank to the fuel filter could be clogged somewhere.