I have an '04 F-350 with the 6.0 and about 70,000 miles. The truck does not currently have any kind of programmer, although the previous owner did have a triple dog installed. Recently the EGR cooler started leaking and I had a mechanic put on the Liberator EGR delete kit. The truck runs great now and the boost is the same as always, but there's a nasty whistle or whine sound from the area of the turbo. I cant tell if theres a problem with the turbo itself or if it's just a leak in the intake or exhaust plumbing around it. Any help would be greatly appreciated.
a littl late on this post, but i just got my 03 350 6.0 out of the shop, and it whistled unbelievably b4 it went in. i too bought a used 03 that had, had a triple dog on it... not good! first it leaves a foot print and it screws up the turbo making it not know what rpm to run. the dealership re learnd the turbo and it runs like a champ, still whistle but now vairies at an idle like its suposed to, and with the new tune the turbo acctually shuts off at idle! amazing! next step egr delete(disconnected for now, by service tech) and sct custom tuned.