Dirty MAF, leaking fuel injector come to mind.
could be an o2 sensor as well
What could be the possible cause of high negative fuel trims when I accelerate? The trims sometimes go as high as -14.2, any help or ideas to resolve this would be appreciated.
It was tuned for the tb, I've had it for over 8 years and this just started happening.If your ported throttle body was never tuned for, then that's another thing to look at.
The conditions happen under mild acceleration from stop, during wot the trims lock at 0.0Something causing your fuel pressure to go to high under WOT. Rare, but possible.