CODES P0171-P0174

Does anyone know why long term fuel trim would stay high regardless of idle or under load? My scanner reads ~35% for both

 

Have you checked fuel pressure?
What's your MAF reading at idle?

 

It looks like 3.8 g/s

I should have noted that I’ve recently had issues with my MAF (code p0101)

Following p0101 I had the Toyota dealershit (not autocorrect) take a look and aside from breaking my U joints they seemed to fix my MAF issue

I also had a separate shop clean my pcv (is what I think it was called)

 

That's about right for a hot idle, checking fuel pressure would be my next step for a lean condition.

 

It looks like my 07 was made right before they required US market cars to have a fuel pressure gauge linked to the OBDII port, will I have to take it to a shop to have them test it or is there a hack?

 

There is no requirement to have a fuel pressure sensor or to make it available as a PID, many vehicles do have one but 2nd gens do not.

You have to tee into the line with a gauge to check it.
The best spot to tee in is under the hood where the lines connect.
You need something like this to tee in.

$33 BETOOLL Fuel Pressure Test Kit 0-100PSI with 9.497.896.30 Fuel Line Fittings

https://www.amazon.com/dp/B07LF26ZTJ

 

Perfect, thank you for the help, this is uncharted territory for me

 

Check the fuel pressure by teeing into the fuel supply line going to the fuel rail.

Tank >> Filter >> Pump >> Fuel delivery tubing >> Fuel Rail >> Fuel Rail Regulator ( Set to ~ 40 - 41.7 PSI) >> Return to tank.

If you tee into the delivery tubing the regulator still works and reads the regulated pressure ~ 40 - 41.7 PSI.

If you dead head a gauge at the delivery tube it reads full pump pressure ~ 60 PSI.

While idling:
Standard: (40.8 to 41.7 psi)
• If the pressure is too high, replace the fuel pressure regulator.
• If the pressure is too low, check the connection between the fuel hose and fuel pump.

Stop the engine.
Check that the fuel pressure does not change for 5 minutes.
Standard: (21 psi)If the pressure is not as specified, check the fuel pump, pressure regulator and/or injector.

 

Update! When I went to test this the CEL dissappeared, only to return a couple engine cycles after I fill the gas tank, CEL usually turns off near half a tank. Any ideas? Trying to find a time where I have free time and the light is on to check fuel pressure. Thanks!