So Ive had a 1998 ranger, 2.5l, 5spd, rwd, since about spring time. Ive dont a good amount of work to it. But the last few months ive had some fairly poor gas mileage, from roughly 400miles to a tank, about 28mpg, down to 300miles a tank, 20mpg. Most of my driving is highway. Ive replaced the MAF, and upstream/downstream O2 with denso sensors, new tires were put on it over the summer, went from 225/70/15s to 235/75/15s because of the greater selection. Pressure tested the fuel system and got 55psi.

Im stumped as to why my fuel mileage dropped so much, I wouldnt think the tires have anything to do with it because it started before I put those on.

Any help or potential fixes/ issues you guys have had in the past would be greatly appreciated.

My next steps are to pull fuel injectors to clean them out.