Hello and thanks to anyone that replies. I looked in the archives, but didn't find the answer I was looking for. I have a bone stock 98 f150 with 75000. I don't have any major problems with the truck, a little bit of a "whine" from the rear differential, and my driver side window goes down slow. Great truck for the 3 years that I have had it. Anyway, would an oil analysis be a good idea? If YES, where should I look for the service and what would the cost be? Also what would be the single most effective modification for better fuel mileage? I get between 13 and 17 mpg. 5 speed by the way.

 

MaroonF150,welcome to ! This website is totally dedicated to oil and lubricants;
www.bobistheoilguy.com
I think you should start with your exhaust and the air filtration system first. A chip would be a good choice after you've done the first two. Stick around; there are a few members here that will help you in the mod section!