2000 ranger, 2.5 with 365000 miles . code 172 replaced all sensors, plugs MAF Pvc fuel pump, ICV, plug wires, EGR. fuel presure 65, did smoke test no leaks. Need other ideas? code 172 means rich, connected fuel presure gauge, turn on key i get 65, But turn key off presure gauge goes immediately to 0. I assume the only possible reason would be leaking injector? any other ideas?

 

P0172 System too Rich (Bank 1)

If you have a vacuum gauge check for clogged exhaust, but this is usually noticed by limited top speed and RPMs on highway

Stop changing sensors!, lol
Unless they are Motorcraft brand 3 in 10 3rd party sensors will be bad out of the box so grain of salt with "new" sensors

ONLY sensors that needs to be changed are O2's every 12 years or 100k miles which ever comes first
My 1994 has all original sensors except for O2s

While it is a popular thing to do it just adds complications to diagnosing issues

The very easiest test for leaking injectors is your nose
When you turn the key off on a running engine then the computer shuts off spark and injectors instantly when engine is still at 700rpms
And engine winds down to 0rpms
Pull off the large air hose from intake, open the throttle and smell, should be NO gasoline smell at all, going from 700 to 0 rpms would have sucked any smells out, blow into intake to get some air movement, leaking injector would create a gasoline smell


For technical test
Do the Clear Flooded Engine test
Turn on key
Press gas pedal down to the floor and HOLD IT DOWN all the way
Try to start engine
It should not start or fire, just spin
If so then you do not have leaking injectors

Clear Flooded Engine is a mode in all fuel injected computers
It allows driver to crank the engine with Fuel Injectors OFF to "dry out" a flooded engine
Most car makers use the same routine
Key on
Gas pedal to the floor
At 0 RPMs and WOT(wide open throttle) the computer will shut off injector pulses and be in Clear Flooded Engine mode, spark will still be working

So if engine starts then fuel could be leaking in, but.......................................
Rangers can get stretched Throttle cables, so no WOT at throttle sensor and no Clear Flooded Engine mode
Key off
Hood open
Put a stick on gas pedal holding it down all the way
Go to the engine and see if you can open the throttle a bit more
If so Google: Ranger throttle cable mod
Its a very simple fix, and engine will be much "peppier" after this fix

If throttle is at WOT and engine started in the Clear Flooded Engine test, then you do have a leaking injector
And easy to identify it using same test
Disable spark, unplug coil packs
Crank engine over using Clear Flooded Engine test, do it a few times
Now pull out 1 spark plug from each cylinder
Look for WET tip, that will be the cylinder with leaking injector


65psi is within spec but at the high end, 55-60psi is usual, but 55-65psi is spec
The fuel pump is capable or 80+ psi
In 1998 and up there is a Fuel Pressure Regulator(FPR) in the gas tank along with the pump, so if you changed the whole assembly then you have a new FPR

So the drop to 0psi with key off would not be normal, so could have a leaking injector or new assembly is leaking pressure with key off