2016 guy

I have a 2016 Canyon 4x4 crew cab V6 with 67k miles. I was getting roughly 17-18 mpg in the city and 23-24 on the highway on long trips. A couple weeks ago I added a bottle of injector cleaner then filled up a full tank . Since then the milage dropped down to 14 -15mpg in the city. I've not been on a long trip so I don't know what kind of mileage I would get on a trip. Did the injector cleaner do something to cause the drop and what can I do to remedy this. Thanks guys for any help.

Hey guys, I I've been getting about 17 miles per gallon in town and probably around 23 on the highway which I think is pretty fair for my 2016 GMC Canyon crew cab long bed 6 cylinder so a couple of weeks ago I dumped you in a bottle and my truck has to start back up a bit my truck has 67,000 just under 67,000 miles on it so I dumped in a bottle of ejector cleaner figuring hey it's not going to hurt anything right maybe I'll get a little better mileage around town and now I'm getting worse mileage now I'm down to like 15 miles per gallon in town I haven't been on a long road trip so I don't know what it's going to be like on the road on the highway but it seems to have dropped at least two miles per gallon in town since I dumped in that freaking bottle of ejector cleaner in a full tank of gas of course I dumped it in first yes get that question out of there and it was in quality it was a quality brand from Shell did this loosen up some stuff to cause me getting worse mileage or what's going on any ideas thanks for all the help.