I have a 2014 Ford F-150, 3.7L, flex fuel STX

EEG

I have a 2014 Ford F-150, 3.7L, flex fuel STX. I filled up the gas tank at Walmart and when I started driving, every time I excellerated, the lifter and calves started clattering really bad. If I go real slow and increase speed very slowly, it doesn’t make noise. It has 120,000 miles and just had an oil change. Where do I start looking. I’ll take it to a mechanic, but I want an idea so I don’t get ripped off.
Thanks,
Mindy
New Braunfels, TX