we have a 2006 ford freestar at shop that under heavy acceration it will surge on 2006 Ford Freestar

normal driving it is fine. plugs,wires ,fuel filter and flow are fine.cleaned intake,injecters and vavles. no codes under globalobd2 or manufature specic. looking for suggestions possibily missing something.

Asked by for the 2006 Ford Freestar
Have you driven / ridden in it with fuel gauge and scanner hooked up?
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maybe a vacuum leak