To start with I drive a 1999 ford ranger xlt with 2.5l m5r1 trans and 3:73 rear diff I went through and replaced every sensor on the engine including o2 sensors and sending units replaced coil packs plugs and wires and replaced the injectors all at the same time on my engine and for some reason I have no power on hills I can drop to 4th gear and pulls fine but will not pull even the slightest grade in 5th engine only has 175,000 and was sluggish when I bought it at 148,000 I know the truck has a 2000 engine with the stock 1999 ecm and am wondering if the ecm is failing because all fuel pressure tests and even compression tests show amazing results even under load the fuel stays at 30psi and compression test shows 1st cyl at 154 2nd at 153 3rd at 155 and 4th at 154 so compression is within reason of error just need help to fix this issue

 

Welcome to the forum

1998-2011 Ranger fuel pressure should be 55-65psi, so yours is low, but it would "feel" like its "running out of gas" at high loads
And I would expect "lean" code as well, neither of which you mention

1986-1997 ran 30-40psi, just FYI

When was the timing belt last changed?
If its a little stretched(old) that would reduce power

Also unplug one coil pack(3 wire connector)
Start engine and drive it, should run smooth but have a little less power
If there is a miss or running issue then there is an issue with spark plug or wire on the working coil pack

Then reverse and test the other coil pack the same way

The point of Dual Spark plugs is that it adds more power, IF all 8 are working, this engine ran fine on 4 spark plugs from 1974 thru 1988 when it was switched to dual plugs in 1989
4 valves per cylinder adds even more power so dual plugs were dropped

 

I understand on the miss fire and will give that a shot but fuel pressure got me if it should hold higher fuel pressure than what my rail shows could I have a bad regulator allowing a fuel pressure bleed issue to where the truck runs and doesn't fault by the computer but not enough for standard driving conditions

 

There was no fuel pressure sensors on Rangers, when engine was running the fuel pump was on full time
Any 1989 and up Ranger fuel pump was capable of 70+psi

In 1998 and up the fuel pressure regulator(FPR) was moved to the gas tank and put on the fuel pump assembly, called a "Returnless" fuel system, only 1 fuel line in engine bay

From 1998-2000 Ford tried putting the FPR on the OUT line of the fuel pump
Seen here: https://m.media-amazon.com/images/I/...AC_SL1200_.jpg

The FPR is the metal round part just above fuel pump(at the bottom) with black hose connecting it to fuel pump, and you can see there is only one fuel line connection at the top of the assembly
This worked, but didn't work well, fuel pressure could jump around quite a bit, as engine load/demand changed

In 2001(and some 2000) Ford changed the design and used a 3 port fuel filter, the 3rd port was a RETURN line hooked to FPR in the gas tank
Seen here: https://m.media-amazon.com/images/I/..._AC_SS450_.jpg

2 fuel lines at the top, Yellow is the OUT, and blue is the Return from fuel filter
This gave the fuel system a more stable pressure

The type of system is not your problem, but the fuel pump or the fuel pressure regulator could be, if pressure is 30psi, but both are changed with new assembly

 

the engine that was swapped into my truck is date coded as an August 2000 model engine so its newer than my truck could that be a problem for the truck because this has stumped me from the day I bought the truck it runs perfect other than being low on power and I know if it revs past 3500 rpm it begins to stutter when you bring the rpm down it takes a few moments but smooths back out I didn't mention it in the original post but the fuel pump was replaced about 4 months ago with an oem replacement

And this is the regulator on my fuel rail that i am questioning
as the photo I attached shows there is some form of a fuel pressure regulator on my fuel rail and I do have a return style tank I should know ive had it off before