Need Help On P0172

[tombugg]

So, quick background, I picked up a 2000 4runner that we are rebuilding (CA model) and just installed a rebuilt motor in it. Everything is working great, running fine, but can not get rid of P0172. We were getting P01300, changed both o2 sensors and that went away and now the dreaded P0172. I have changed the air filter, fuel filter, new injectors, new MAF. The one thing that is bothering me is my fuel pressure is at a constant 45psi even when I remove the vacuum sensing line going to the intake resonator,.. nothing changes. I cant figure why there should be any vacuum from that?? Anyhow, I disconnected that and plumed in the vacuum line so that it does go down to the 36psi, but now throttle response it stumbles a bit and still throws a P0172?? I have been chasing this for months, and have researched all the boards. I found one post about the same fuel pressure issue with no follow up as to what the cause or fix was.

Please help!!!

Thanks

Tom

 

[tombugg]

Some more info:
STFT -17
LTFT -27
Looks like it is getting too much fuel.. I put new fuel injectors in a year ago and am thinking one of them is leaking or bad.. The LAST thing I wanted to do ... AGAIN

 

[TucsonMike]

Is the throttle body clean and is the butterfly valve in there opening and closing okay? That was the issue with mine though it was my sequoia not my 4runner.

Mine was seeing similar trim values or worse.

Good luck

MikeM

 

[Dylan3rdGenT4R]

Hello new to the forum and using Tapatalk so I can’t tell how old this post is but did you ever figure your issue you? I am having almost identical symptoms and it’s driving me crazy


Sent from my iPhone using Tapatalk

 

[Granulated_sugar]

Did anyone ever get this figured out? Im having issues with my p0172 and have tried many things.

 

[spartacus]

Did anyone ever get this figured out? Im having issues with my p0172 and have tried many things.

My p0172 was caused by a bad up stream o2 sensor. but dirty or bad maf, vacuum leak, exhaust leak, leaky fuel injectors. pcv valve gummed up could all be the causes.