Hi Chris.

Sounds similar to a problem I had. The same experience only on an a-road with traffic coming at me. thought I was sent for.

Have the boost pipes checked by whoever fitted the intercooler as some of the may not have been tightened up fully. Boost leaks can be a cause of similar symptoms.

Is the fuel filter genuine ford? Some aftermarket filters don't flow as well as the ford ones or the aftermarket bosch filters.