When you get a fuel trim error it's usually dirty injectors not getting enough gas in, low fuel pressure or O₂ sensors reporting the wrong O₂.

Vacuum leaks usually throw off the values so fast you will get a vacuum leak error.

Every car I've worked on that had a fuel trim error was either weak fuel pump or end of life O₂. (upstream).


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2011 E70 • N55 (me)
2012 E70 • N63 (wife)