mcc23

I cleaned out my EGR valve a few weeks ago and I keep getting CEL with a p0400 EGR flow code after 10-20 miles of driving. One of the 10mm bolts that holds the valve in place will not torque down to spec. It barely gets about 50% of the torque I need. The assembly feels snug but I know this bolt is not as tight as it should be. There was a bunch of metal shavings on the bottom half of the torx bolt when I removed it so I'm wondering if perhaps the lower half of the hole has some sort of buildup, preventing torque being applied to the bolt. Before I chase the thread, I want to see if I can get some sort of suction onto the bolt hole to remove any of the buildup. I was unsuccessful with compressed air. Any thoughts about what else could be throwing this code? Thank you!

tjts1