Did you take out the wrong screw when you wanted to take out the LPR set screw? One is an air seal screw. One is a set screw to lock the LPR in. Double check. If you took the air path screw out, then it's probably leaking.
If you didn't then it's possible you have a cut oring on the outside of the LPR and it's rolling over. This can cause the LPR to seize up rather than come out smooth. Remove the adjuster screw, then find another random long screw that will fit into the adjuster screw hole. Use that as a handle to tug the LPR out. Make sure you use something with similar threads...don't just jam any old screw in there.
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