Greetings Wise Ones, This is my first post and I'm currently exploring the site, so please pardon me if this question has been asked a million times. I recently purchased a used 2008 Ford F-150 4x4 with a 5.4L 3-valve Triton engine. Ford's recommendation is to use 5w-20 and I was curious how much of a difference would I have using 5w-30? I just recently completed my first oil change using Mobil1 synthetic 5w-20, but I can buy Mobil1 5w-30 at my nearest Costco and save a few bucks. I live in Atlanta, GA where the summers are hot and the winters rarely cross freezing temperatures. What could be expected by using the 5w-30, instead of the 5w-20? I'm sure mileage would be impacted, but would it really be significant enough to take notice? Also, I have read that using a Synthetic oil allows you to extend your oil change intervals, but is there any suggestions of how much longer it would extend it? I generally change my oil ever 5,000 - 7,500 miles.... would I maintain this interval? I have an equal mix of City vs. Highway miles. Thanks for taking the time to pass on your wisdom.