Anyone else's truck do this?

I picked up my 16 crew cab with 14k in it, it now has 62k on it. Dealer has done every oil change at 5k ish since I've got it.
Every time I get to around the 4k mark or a little past the truck starts getting sluggish and loses 1.5-2 mpg.
Get the oil and filter changed and it gets more pep and right back to the same mpg as before.
At first I thought it was the air filter, cheap fuel, or winter/summer blend change but I've paid close attention the last 3 changes and it's none of those.
So, does anyone else's tundra do this and does anyone know why the hell mine does?

 

What oil you putting in it, that stuff the dollar store got sued for because it was made for pre-1930s leaded engines? Just teasin' ya, if your serious about this actually happening, you might want to find out what your dealer has been putting in your truck.

 

Agree with Gravy - first thing that comes to mind - what kind of crappy oil are they using?

I have a 2016 with ~60k miles on it too. I change oil every 5k as well. I’ve never noticed a difference between mile 1 or mile 5000.

I do my own oil changes & use Mobil 1 & OEM filter. I won’t take my vehicle to a shop for oil changes anymore (not even to a dealer) after hearing the horror stories of others & experiencing one myself.

Do your next oil change yourself. Use good oil, OEM filter, and see if there’s a difference. I suspect there will be. Then never go back to that shop for an oil change. Maybe even share with them the difference in performance you may see.

 

(44) Bacon Grease as Engine OIl? Let's try it! - YouTube

I always liked Mobil 1 (Grampa owned a Mobil station when I was a tyke, always been biased since ), after doing a lil' bit of research, think im going to be switchin to Pennzoil Ultimate Platinum. Mobil 1 is still plenty good, but looks like theres several modern full synths now that outperform it by quite a bit.

 

I'm beginning to wonder myself on the oil. It's billed on the sheet as TGMO 0w20 but honestly who the hell knows.
I kept using them because I bought a 16 4runner from them and got the first 3 changes on it for free. Never had a problem with them or noticed any issues so I just kept on with them when I traded for the tundra. It was a few dollars cheaper than I could do it myself and no hassle involved.

Now the price has gone up and I want to see if there's a difference in a known quality oil and what could potentially be cheap barrel oil getting passed off as TGMO.