Unplug the MAF(mass air flow) sensor and go for a drive, CEL will come on, see if things change for the better or worse.
4.0l MAF sensor should be cleaned every few years.
If CEL doesn't come on then you could have a computer problem, assuming CEL does come on and go off when you turn on the key.
1998 Ranger 4.0l doesn't have a fuel pressure regulator, so can't leak fuel into the intake, sending MPG down.
So you are left with incorrect MAF data or incorrect computer calculations of fuel
O2 sensors can't skew fuel needs that much and I doubt 2 would fail at the same time.
What do the spark plugs tell you about engine condition?
Are they dark brown or blackish meaning rich burning, or do they have a light brown color for correct burn.
Does the engine run better cold and then start to buck after 5 minutes of running?