Working on my grandpa's ford flex. It will start but won't hardly idle and no throttle response. Pulled codes i don't remember the numbers but they were for o2 lean both banks.
To me it acts like a large vacuum leak. I couldn't find any or hear any.
I unplugged the MAF and it starts and runs as good as can be expected with the MAF unplugged. Running like this i still couldn't find a vacuum leak.
I'm leaning towards thinking it's a bad MAF. I looked it over and it looks clean. I just wanted to confirm with someone smarter than me before I spend $100.