QX80 Running like a billionaire's car- need help!

[vienno619]

Got me a QX80 2016 model with 150k mileage and it's burning fuel like crazy. I think it's got some fuel economy issues, it runs 14-16mpg on a gentle highway and 9 on a city. Got it with new engine oil/filter, new air filters, some good looking sparkplugs and no bad smoke comin' out and its still bruning too much juice. So my question is, what happened to the 2mpg specs claim? Lol. Btw, the O2 sensors look okay and responding nice, though long term fuel trim too high for ex. 28% bank2, bank is good. Intake manifold abslute pressure is consistent but too low at .29 psi and it doesnt change. MAF sensor all good and responding correctly to the throttle, it goes about 6 g/s when idle and 20 on throttle. All else looking good on the scanner except the P219A air fuel ratio imbalance bank 1, so i guess thats where the issue is. Bought a 2016 infiniti qx80 MAP sensor at partsgeek, it looks like this.

Questions!!!:
* did i buy the right piece? cant really find anything similar under the hood, can anybody tell me which part should be looking?
* what else should be checking on for a case like this?

much appreaciated! cheers

 

[8BitAlchemist88]

Yeah, sounds like you're chasing down the right path with that P219A code, but here's the thing — that MAP sensor you bought probably isn't the right fix for your issue. The QX80 doesn't rely heavily on the MAP sensor like some other cars do. The real player here is the mass airflow (MAF) sensor since Infiniti's V8 is tuned to depend more on MAF data for air/fuel mix adjustments.
Actually, back in the early VK-series engines (like the VK56DE in your QX80), Nissan/Infiniti had issues with carbon buildup in the intake manifold and throttle body that could mess with airflow readings and cause a fuel imbalance like what you're seeing. Cleaning those parts might help. Also, check the PCV valve — if that's stuck, it can throw off your fuel trims too.
Lastly, don't sleep on vacuum leaks — they're notorious for causing weird fuel trims without throwing clear codes. Try smoke testing the intake system just to rule that out.