I doubt your scores will fall 100 points when you pay off your car loan, as your credit is already very strong. Depending on what property taxes are where you are buying, and how much you plan on putting down, your debt to income ratio could look OK or it could look a little on the high side. If you go with conventional financing, a 100 point drop would affect interest rates, but if you go with FHA then a 100 point drop wouldn't have any affect on rates.
Free Mortgage Advice & Pre-Approvals (FHA, VA, USDA, Fannie, Freddie, Non-Prime, Construction, Renovation/Rehab, Commercial) since 2002
Located in Southern California and lending in all 50 states