I have a 2017 Chevy Traverse. A while back my mass air flow sensor had went out. I didn't know it was the mass air flow sensor right away, it just lit up the check engine light and started not wanting to accelerate and seemed like the engine was choking. I started with the air filter, replaced that, then I went and had it plugged in to the reader and it came back my purge valve was no good, replaced that, still had the same issue, just kept getting worse. Went and plugged it back in again and results were bank 1 was running to rich. I wasn't really sure at that point so I started watching videos and stumbled across one that said it could be the Mass Air Flow Sensor, replaced that, and fixed the issue right away. Before this all happened I would average a out 17.3 mpg but during the time spent figuring out what was going on the mpg had dropped to around 5 or 6 mpg. After replacing the sensor it jumped back up to 12 mpg but never any more then that. Now, about 3 months later I'm getting 9 mpg. I've checked my air filter multiple times as well as the housing and intake tube, and replaced my spark plugs. What can I do to fix this issue. No check engine light is on and the rig seems to run just fine other then the mileage.