Lean codes bank 1 and 2. 2003 Sienna

This 2003 Toyota Sienna runs a few days then Cel code P0171 and p0174 Running lean banks 1and 2. Cleaned Pcv, new maf, new o2s, can’t find a vacuum leak. Cleaned throttle an IAC. Starts and idles well. Slight hesitation on acceleration. Does this fuel trim chart look normal? Any thoughts?

Need more data.
Can you read freeze frame data? What does it show?

I’d prefer PID values over graphing if possible
What are fuel trims at idle?
What happens when you increase the rpms at idle holding at 2500 and 3000 rpms? Do they get better? If so, vacuum leak.

Do your oxygen sensors go full rich during WOT on the road?

What is MAF reading at idle in grams per second?

Thanks for reply John C.!
Lets see if I can answer your questions.
FT at Idle STFT1 = +5, STFT2= -8 , LTFT1 +20, LTFT2 +19

LT Fuel trims do get better when I Increase RPM.
AT 1200 RPM Long Term is 22
AT 2000 RPM Long Term is 10
Short term jumped around a lot , I did not see a noticeable change.

Oddly the start up Idle was at 2000, unusually high today.
Cold Idle @1200 RPM Maf was 5.7
After a few minutes @ 800 RPM MAF was 2.65. Engine is a 3.0L

I'm not sure what PID values are. Is that the voltages, or just the numbers reported? My OBD2 is WIFI read by my phone.

I am not sure how to tell if O2 goes fuel rich at WOT.

From your reply. It seems I have vacuum leak that I cant find. So far I've checked rubber intake snorkel 2 times. hose clamps are tight. Replaced one crispy vacuum line to valve cover. I have not checked brake booster yet

My MPG is great 26 to 28.

Possible brake booster issue. Try pinching off the hose and see if trims immediately improves.

I'd also like to see the A/F sensors go rich during a WOT run through first gear, and see them go to full lean during a fuel cut deceleration. What PIDs do you have available for the upstream (B1S1 and B2S1) sensors?

Very cool. Your edit comments to graph. I’m just stumped. On were the leak is

Great! I’ll drive around the block and hammer the pedal when I climb a hill. Stay tuned.

Just went booking to the store. The first maf peak is me hammering the pedal. To 6000 rpm. Then 8 mile drive to store going easy.

I did a brake booster test. Press to floor. Start engine. Pedal depresses a bit. Seems like booster is ok. The vac line is behind the filter and maf. I’ll have to take it apart to check booster line. I need to find a smoke to do a smoke test. I have washed a garden hose over the engine an did not get a stumble. Cold engine start

Not sure what you may have done to check vacuum leaks, BUT, if you do not have a smoke machine, introducing propane fuel and closely monitoring the STFT can help identify a leak.

Using a propane torch, unscrew the Air/fuel element at the burner end of the torch and add a nice length of rubber hose. This makes it possible for you to leave the propane on (gently) just a small hiss with the can remaining upright. On the other end move the hose SLOWLY all over the intake manifold area, Canister Purge valve, all vacuum lines, while monitoring the STFT's. When Propane gets 'sucked' in the STFT will immediately respond by going Negative. Don't be fooled by a false positive if the propane does enter the air tract properly. You can actually try that first as a test so you can see the response time for the trims. That will give you an idea of how slow to move the hose.

Based on your fuel trims responding by getting better at higher engine load/rpm, I would tend to believe fuel delivery is adequate, otherwise, they would be going Positive at higher load/RPM due to lack of volume/pressure or restriction.

If the MAF was underreporting, 'dirty', your trims would go further Positive at high load/rpm.

With fuel trims improving when RPM increases that does lean toward a vacuum leak.

For checking fuel delivery I find it helpful to graph the TPS and both upstream O2's at the same time. Then you can correlate your wide open throttle event with the O2 sensor data. On Toyota you need to be careful, though, as many use air/fuel ratio sensors which work different than a traditional narrow band O2 sensor. When you mash the accelerator, your O2 sensors should go full rich, or around 800mV and stay there the duration of the wide open throttle. If the drop lean then you could have a MAF or fuel deliver issue. You don't need to overrev the engine but just give it 3-5 seconds of wide open throttle.

If your vehicle has air/fuel ratio sensors for the upstream sensors then reading those is a bit different than a traditional O2 sensor. You have to watch the voltage on the scan tool and voltage above 3.3v is lean and below 3.3v is rich.

Alright! I have propane torch someplace and will give it go on hoses and things

I found a way to post o2 volts and will do that today

Below is a throttle position and o2 chart

The idea is to have the TPS and O2 sensor graphs running as the same time so you can see your WOT run and your sensor voltage. I see a short duration of full rich in your O2 graph but no way to compare it with the TPS at the same time. The O2 should stay rich the whole time the TPS is maxed out.

I agree with John, it is good gather WOT data to rule out a fuel system. If you can can you also graph/record what the Intake Manifold Pressure is at when the throttle blade is wide open. For example, if the BARO pid is showing 29", and at idle the Absolute Map Value is say 9", this would mean you have 20" of vacuum in the intake manifold. Upon Snap throttle you want to see that 9" at idle rise within 2" of the BARO 29"-2"=27". Anything less than 27" would mean you have an air restriction, ie, the motor is not expelling air at the same rate it is inhaling air.
If you rule the fuel system out for John, rule out a breathing issue, then we can focus on the vacuum leak.

I bought a propane tank and poked around all the fittings etc. no change. I start wiggling the brake booster lines and now LTFT. Is at 40%. I unplug the vac line to the intake manifold. Plug hole with my finger, It stays at 40%. Had to remove wiper cowling to get to that part of engine. I don’t have a manifold pressure reader at this moment

What’s the oxygen and air fuel fuel ratio sensors reading when the fuel trims are that bad??? Can you post fuel trims in one pic. And oxygen sensors in the other with rpm

Here is pic with me running the wot. Just 5 minutes ago. I’m tromping on the gas pedal .

From the looks of things I should have bullet holes in the intake.

Cheryl, I don’t have many o2 volts to show. Here are trims. And rpm and some o2 volts

One find from the brake booster line check was that the vacuum lines are stiff and not flexible, I can move them with the clamps on. They may leak a little but the propane and other spray tests did not indicate any audible or graph stumble.

If your worried about the brake booster and hose. Just unhook it’s from the intake and plug the port off.