Need ideas. Have a 97 F250 4X4 extended cab with almost 300,000 miles. Bought when it had 244,000 about 4 years ago. Never had any other problems other than replacing Alt and water pump. Yesterday it started acting different. Going down the road from a stop, Shifted good (automatic) until it shifted to Drive. Then it felt like I hit the brake until it downshifted on it's own. Was told it was probably Fuel Filter so I changed that and the air filter, still the same.