I bought this 2014 F-150 Lariat last month trading in my 2011 XLT with 180,000 miles. I took the truck for a test drive but never noticed the vibration because of the older country roads. My 2011 XLT was really smooth and never had a problem. The only issue I have with this truck is a consistent vibration while driving. This vibration is always at 30 MPH and 80 MPH. I already checked the following to no avail:

1. Balance and rotate tires - Nope

2. Check for broken steel belts - Nope

3. Tested 4 different tires AND wheels from my 2016 XLT - Nope

4. Replaced the transmission mount - Nope

I am running out of options. I thought about the cab mounts, drive shaft, and shocks but I still get the same vibration at the speeds you always travel. 30 MPH in the city and 80 MPH on the Interstate. I went on my first road trip this week (1200 miles). I can't drive the truck in this condition. It's fricken driving me crazy. I bought it from a dealership trading in my previous awesome truck that was upside down.