If it's just LSPDFR crashing, try reading the crash logs from the F4 menu. If there is, find the source of the crash and uninstall/update the mod to see if there's any results.
If it's GTA 5 crashing, try taking several plugins out of your folder at a time and hope for results.
If neither of these work, try verifying your game files or reinstalling LSPDFR or Rage Plugin Hook.
When I ran into this problem, my problem was the callout manager mod. If you have it, try that one first.