For the pork loin: Start by seasoning the pork really well all over with the garlic salt, Cajun spice, and the brown sugar. Then using your hand, pat the pork with the oil. On the grill or grill pan and medium heat cook for 8 to 12 minutes, rotating every couple of minutes. After the pork is five minutes from done, add the barbeque sauce and rotate so that the sauce sticks.
Remove and slice. Serve with Sauce.
For the sauce: In large sauce pan add the oil, heat the oil just a little and add the garlic, shallots, jalapeno; saute for 2 minutes, then add the remaining ingredients. Mix well and bring to a low simmer until sauce is combined. Check the flavor and adjust the sweetness if you like.