The problem started about a two weeks ago. Cruising down the interstate about 75 mph the turbo loses about 5psi feels like you hit strong head wind only for a few seconds. Then it right back up. Does not happen all the time. I made some calls and inquires and was told it might be the inter cooler boots. So I changed them and it still did the same. Now keep in mind it only happened at high way speeds (turbo at about 18 to 21 psi) So I called a shop and they said it was probably fuel related so I changed the fuel filter which I do at every oil change (10,000) oil is mobile one full synthic with K&N oil filter. Now when I get back to work I brought it a shop and they couldn't duplicate the problem and tell me it might be an injector. Now the injectors are new, well 60,000 miles 1.5yrs . the pick up pump is only about a 1.5yrs old as well.

Any ideas