[Blue Bowtie]

We will need actual information to make any lucid recommendation(s).

First, what is the measured fuel rail pressure with the pump running, engine off?

What is the fuel rail pressure with the engine running?

Does the fuel pump pass the volume test? That would mean the pump can deliver one pint of fuel (free flow to a catch canister) in fifteen seconds?

Is the IAC clean. lubricated, and functioning? Are IAC air passages clean?

Obviously, at least one repair facility has dipped into your wallet based upon a guess rather than a diagnosis. We'll try to avoid repeating that, but need your input.