[FIXED] Fuel Trims Analyzing - Pending Lean Codes

Care to share the fix with us?
I notice the MAF is not reporting in your final captures

After six days of driving with a new MAF sensor from Ford and watching scan data I can confidently say its fixed! The Duralast MAF was under reporting. After all the testing methods I've done, the last being the injector balance test, MAF had to be the culprit skewing the fuel trims. Especially installing a new fuel pump just for the sole purpose of doing the injector balance test because of the previous bleed down issue. The injectors tested good and props to Paul for showing how to do the test from the computer since the manifold covers the injectors. I had to be $225 sure and it turned out to be correct. If there is one thing I learned is when it comes to electronics go OEM, not the Auitozone or Advance Auto parts kind.
The image below was Duralast sensor



New Ford MAF and 150 miles later engine idling



Engine D or R gear

For some reason I can't get the subject title to say Fixed

Charles Acosta wrote: For some reason I can't get the subject title to say Fixed

I got it. Thanks for following up with this one!

Hmm im having a similar issue with my 1999 Ford Mustang GT with the 4.6L SOHC 2V Engine. My long term fuel trims at Idle are 25% and at 2500 rpms they will go down but remain in the 15-20% range. Ive noticed the Short term fuel trims are also pretty high reaching like 33% sometimes at cold starts, then they can go close to 0% or negative 3% or one will be close to 0 the other will be 22% or both will be high. Ive changed the intake manifold, the gaskets for the intake, also the injector O rings, ive checked all the connections for the vacuum hoses to make sure there are no vacuum leaks. I even sprayed carb cleaner all over the engine and did not see any change in fuel trims. I swapped the maf sensor with another used maf sensor from ford and no effect, both seem to be working fine according to the g/s per second. (6-8 g/s per second depending on the idle speed, the idle is around 900rpms because the screw was raised a little.) and at 2500 rpms it read around 17 g/s per second. Im honestly stumped.

Does your Mustang have low power during WOT acceleration? Or, if you watch both upstream O2's while at WOT through first gear, do they both show over 900mV? Knowing this would indicate if a fuel pressure check is needed.

Well I dont feel a lack of power on the car. When ive been at wot ive never seen the o2 sensors rise to 0.9v the most theyll go is like 0.5ish volts.

I actually havr a feeling the PCM might be bad because the idle is always off and the car stalls sometimes even after changing the iac it would be the same. Also no matter what i had done the fuel trims are always maxed out by 25%. Another thing i noticed is in Mode 6 for some reason there is data for cylinders 9 and 10 but this is an 8 cylinder. When i put mode 6 on my v6 it only shows 6 cylinderd there.

Be careful with Mode $06. It can often report extra cylinders, and is no way indicative of a bad PCM.
If your O2 is not getting near 0.9V at WOT, I'd suspect the O2 sensor.

Edit: I should be more clear, companies like Ford often will show more cylinders in Mode $06 then are on the car. I'm not sure why, but I suspect it may have something to do with Ford needing to add some dummy readings in their monitoring subroutines to fit the OBD2 architecture.
Regarding your stalling and bad idle, does the car startup and run ok when cold, but then start to show issues when in closed loop? If so, that and the fact that your O2 is never going rich would have me looking at the O2 (sensor or circuit).

Guys I am suspecting this might be the problem with my car. I am somewhat convinced my car is suffering from air fuel improper mixture caused by either upstream oxygen sensor or MAF sensor, and Toyota company was billing me for new PCM and new CAT.
Toyota Avensis Verso 2002. When I bought this car newly I was advice by Tyler to clean the MAF, and that brought down the fuel trim significantly but unfortunately I still had drivability problems...when I fully press down the gas pedal, the car would not move or pick up fast as it should, almost like I am losing around 40% of the power of my engine capacity. This problem brought about CAT P0420&P0430 codes.
I have tried to swap my MAF with another Car’s MAF, I have used 3 aftermarket MAF also and same problem.
More background info about the car
The downstream oxygen sensors were correct, the upstream sensor on bank 2 sensor 1 was correct, but the previous owner wrongly used a Volvo sensor in the upstream bank 1 sensor 1 and then also all the 4 sensors wire were cut and re-taped which draws so much attention that the previous mechanic suspected the car’s problem was oxygen sensors related.
I bought brand new OEM upstream sensors bank 1 sensor 1 & bank 2 sensor 1. After some months I went back to the toyota dealership since the problem persisted and the guy checked their system again where they check for part numbers and cancel the part number previously written and sold to me on bank 1 sensor 1, and also Toyota seem to have different Ohms readings for the upstream sensors (1.1ohms) and (1.8ohms). It’s crazy that a big company like Toyota can engineer parts with so much confusion for its end users. They have Multiple ohms readings and multiple part numbers for the upstream sensors.
Bank 2 sensor 1 (89467-42020)
Bank 1 sensor 1 (89467-42010) **this particular one the Toyota dealership canceled it and later wrote (89467-44030) but right now I have 89467-42010 installed in the car.
I tried to check eBay.....pls see attached image
Now I need help to narrow down my problem
1. My MAF volumetric efficiency seem wack...see image showing around 48 grams/sec at WOT around 7,000RPM when it should be above 110grams/sec, and also this might be caused by a restricted exhaust.
2. See image of the OBD gas emission...note it only fails on bank 1 sensor 1 the one Toyota dealership changed the part number
3. Is my problem a MAF problem or that conflicting part number in my upstream sensor bank 1 sensor 1, what should be the right sensor and ohms readings...unfortunately this Verso is not listed in USA. Guys pls help a brother out, I don’t want to spend any more money that is not needed without knowing for sure what the underlying issue is or the correct failing part.
4. Can I do an exhaust restriction test correctly even with a bad MAF or bad upstream sensor, and what’s the bestway to do this test. I have taken out one upstream sensor before and drove without it to do the exhaust restriction test and it was same drivability problem.
****GOOD TO KNOW***** This car never had any CAT DTC’s before until immediately after I installed the upstream sensors from Toyota dealership, but the drivability loss of power problem was same before and after the installation of the new OEM upstream sensors.