Jim Grant's Tech Tips
'88 Mercury Cougar, Fuel Pressure Question
I have an 88 Mercury Cougar with a 5.0 ltr. with fuel injection..
It doesn't have any power past a 1/4 of acceleration, it seems to just
fall flat. I have replaced the fuel pressure regulator, the idle speed
control, and the fuel mixture control. I was wondering if maybe I have
a bad fuel pump. I checked the pressure and it reads 40 at idle and 20
when accelerating. What is the correct pressure for this vehicle? Or could
it be an electrical problem? (Alternator output, coil output, or Ignition
Just so you know, the fuel pressure is suppose to climb when accelerating
your vehicle. If the fuel pressure is dropping, the fuel pump has a problem
or there is a restriction in the fuel line. Have you replaced the fuel
filter? A plugged/restricted fuel filter will cause the pressure to drop
when the fuel is most needed.