hi, i am new to this site and have been searching the web for answers. first i would like to say off-roading toyotas have been my passion for 8 years now and two years ago i bought an 01. i own an 84 and 87 (yes still carb.) so fuel injection is new to me. not only is that new the 01 i bought is supercharged and well now im learning and dealing with a whole lot. well has ran great til the truck came up with p0300 and p0304, a big issue that i have been trying to fix myself. what is needed to know is that my fuel pressure is at 28psi and i know it should be 40 43 psi. the truck has the free fmu mod and wonder if the fpr is bad or why else would the pressure low. i read that if the fpr is bad black smoke or the pressure would be high. please help and yes im a carb guy learning the new.

 

so no luck? well i guess i should have explained alittle more. the truck is the 3.4 so far i have put a new fuel filter, plugs, wires, checked the resistence of the coils. the truck started this with a miss i could hear in the intake before the check engine light came on. the truck has a rough start and that is when i can hear the miss, a few seconds and the the truck runs fine. any suggestions well be nice

 

hum? no help with this i guess, i would even take "go read a book" or just feel like im welcome to this site. not one reply but hundreds for stupid sound systems, i have one of those like a custom blow-through all eclipse but i am looking for help with something serious so then later you sound guys can see a real toyota with a real system. im not an *hole but this site has my blood pumping and i guess venting right now is all i can do. sorry for my actions, i will go else where. peace!

 

I know it’s been 16 years since you made this thread, but I have a 2004 3.4 Tacoma that is having the same issues, I’ve also replaced everything you’ve replaced and the problem is persistent, I’d love to know if/how you fixed this issue.

 

Replacing the fuel filter isn't a bad idea, even if it isn't the problem.

How do you know it's low fuel pressure? Have you tested it with a gauge?

There aren't really too many variables in the fuel pressure area.
1) The fuel pump isn't putting out enough volume/pressure.
2) The FPR isn't working properly and allowing too much of it to return to the tank, regulating at too low of a pressure (or just stuck open)
3) Physical blockage in the fuel lines (fuel filter being one place that can get clogged more easily)
4) Leakage inside the tank - there's a small hose between the pump and the fuel sender.