Drive an 87 TA 350 auto with rear mount turbo.
Installed a walbro 255lph pump and installed the dedicated power line to the pump, although the pump seems to loose pressure after an hr of driving, almost same symptons when you run with stock wiring to the pump to the point of stalling.
Another thing I noticed is the main fuel line feels like its pulsing when the car is running.
When the key is on and the pump primes it doesnt hold pressure either, just drops to 20 psi from 43 psi although with the car running it runs at 43 psi.
Pump is new and have tried 2 walbros, new injectors, filter is farily new and adjustable fuel regulator is few months old as well.
Any ideas would be appreciated.

 

Are you installing the pulsation dampener between the pump and fuel sending asssembly? I have seen these leak. I always replace them with a section of fuel line.

 

Is that the peice of fuel hose that goes onto the fuel pump to the sending unit?
If so the pump came with it and its fine, no leaks, tested the pump out of the tank as well.