i have a 1994 e350 cutaway van with a 5.8 in it

i had a problem when you nail it it would loose fuel pressure, down to about 20 psi

fuel pump was replaced

also the fuel pump regulator and fuel filter was replaced, vehicle has 230k on it but the motor is new

now when you nail it the fuel pressure goes from 60 to 10 so fast that the guage pointer is a blur!!

i checked the lines and do not see any bends

any ideas would be great!!!

 

sounds like a fuel preasure regulator to me 60psi at idle is too high, to start with.

 

Just a guess-->
Could the Pressure Feed and Return lines be mixed up?

-J-R-

 

its a new regulator, and when your driving normal your at 35-40 psi

when you give it full throttle is when the guage fluxuates like crazy from 60 to 10

it even does it with the vacumm disconected from the regulator