New member hoping for some help

Hi, My name is Eric from NY. I've watch the repair videos here and it just amazing how things can be figured out with knowing what to look at. I'm hoping some one here could steer me in the right direction. Here's my problem, I own a 2015 Nissan armada 4x4 with the 5.6.engine 91300 miles. Back in Nov I went for an inspection and the truck failed because of the o2 sensor and egr sensor not ready. I was told to drove the truck. Well after 850 miles and many drive cycles later I still had the problem. I then took it to Nissan and they had it for a week driving it to make it ready. After 5 days I took it back to drive it myself again after paying them 190. to do the same. After another 300 miles over the weekend I took it back to Nissan on Monday and told them It has to be something other then just driving it. After another week there they told me I needed 4 new cam shaft position sensors. They change those out and got the truck to pass inspection but when I picked it up the o2 monitor light was still not ready. I then replaced all 4 o2 sensors myself and it didn't make a difference. a week later the check engine light came on with PO171. I took it back to Nissan and after three days they told me they reset the ecm and its fine. I picked the truck up and an hour later the light was back on. I then tried replacing the MAF sensor reset the ecm and drove 42 miles and the light came back on. O2 sensor not ready is always lit. Both fuel trim levels are below 10 % I found online how to build a smoke machine and I checked for vacuum leaks, all was good. rather than going back to Nissan I took the truck to a local shop. They checked the vacuum, it was OK .and told me the bank 1 down steam o2 sensor was reading a little off so they replaced it again reset the light and told me to drive it. 42 miles later the light was back on. I now drive everywhere with my scanner in my hand watching the live feed. This is what I found and have no idea what it means. driving on the highway around 1800 rpm the STFT on bank 1 goes from normal to 25% and stays there for as long as I keep pressure on the gas pedal doesn't matter what speed, as long as there is pressure on the pedal. then longer I drive like this the higher the LTFT on bank 1 goes. once up to 32%. As soon as I release the pedal the trim level on both short and long goes back to normal but by then it set up a PO171 pending and then stored. I took a complete video of this but have no clue what it means. The other problem I have is I ordered a new truck thats due around Feb.18 and this Armada is being traded in so I'm running out of time. Thanks for taking the time to read this, I'd love to hear any thoughts you might have

I've moved your post to the Repair section.

driving on the highway around 1800 rpm the STFT on bank 1 goes from normal to 25% and stays there for as long as I keep pressure on the gas pedal doesn't matter what speed, as long as there is pressure on the pedal. then longer I drive like this the higher the LTFT on bank 1 goes. once up to 32%. As soon as I release the pedal the trim level on both short and long goes back to normal but by then it set up a PO171 pending and then stored.

This is an indication of poor fuel delivery. Check fuel pressure and make sure that it maintains within specification under load.

What do the bank two trims do under load?

bank 2 fuel trim is always normal under 10%

wouldn't that cause a problem on both banks

jemjem wrote:

wouldn't that cause a problem on both banks

Yes, it would. My apologies, I read too fast and didn't pick up on the fact the there is a bank-to-bank fuel trim imbalance.

I would, still, be paying attention to fuel delivery, though. Specifically, the injectors. Maybe, an injector balance test will show something?

I’ll definitely check it out. Thanks for the suggestion.

ordered 4 new Bosch injectors for bank one. Hoping that takes care of it. Will have them Friday. Fingers crossed

well replaced all four injectors in bank 1 with new Bosch injectors and still have the same problem throwing code PO171. I can drive unlimited miles without throwing the code by watching my live feed from the scanner and when STFT randomly jumps from normal trim to 25% I take my foot off the gas pedal for a second and the trim level returns back to normal. This happens on and off only while drive on the highway and as long as I keep resetting it, I won't get a PO171 pending. If I don't reset with the gas pedal it goes pending and then sets off the check engine light again.