Hi Guys, I recently bought a 2004 F250 with the 6.0 PSD. Ever since i had it, the boost would fluctuate slightly under load or cruising down the freeway. I recently welded my EGR cooler shut and cleaned my oil cooler. I removed the turbo and cleaned it all up. I put everything back together and its worse! I had an exhaust leak at the clamp to the EGR cooler. Fixed that but boost still fluctuats. You can hear the turbo whistle fluctuate up and down through out the power band. Installed a boost gauge and you can see the needle move up and down, up and down. Replaced EBP sensor, cleaned tube, cleaned MAP sensor and nipple and hose. Cleaned IAT nipples. Removed IPR valve and cleaned. Ran scanner and everything seems to be withing spec. Only fluctuation i see in anything is the EBP sensor is showing the fluctuation. Removed turbo 6 times to verify everything was OK. Install custom tunes to see if that would help, Nope. Any advice would be appreciated. Thanks!