I have a 90 4runner V6 m/t.. Did a fuel pressure test today and when it's idleing the fuel pressure is between 37-39 psi.. But as I slow increase the throttle up around 2500 rpms the fuel pressure would start to drop to zero and then die.. Any thoughts?

 

Could be a few things.

China built fuel pressure gauge??

Will the engine idle as long as you want??

As the pressure drops the engine stalls

Fuel filter blocked the pump can`t push it through fast enough.

Your circuit opening relay is dropping out and the pump shuts off

The pump sock is full of rust so it can`t keep up with demand

the pump is on it`s last breath before it dies.

 

While fiddling with a few things today I'm not 100% sure but seems to run better when vafm is messed with.. It's got a new fuel filter..

 

If for some reason The AFM is not adjusted correct or getting old or tired it will cause the fuel pump to shut off.

Could just be a poor or corroded connection could be some foreign object blocking the door .

Things do wear out our trucks are no longer new.