I have a 1998 Ranger 2.5 L , 5 speed . I’ve replaced Fuel pump , fuel filter , fuel filler neck ,TPS sensor , Crank sensor. It’s only throwing a code from O2 sensors but when you rev it up , it’ll cut out like it’s in limp mode. I replaced the Throttle positioning sensor today and it has better throttle response and runs a little better but it still cuts out. Any idea? We tried looking for vacuum leaks and nothing and looked at MAF sensor and nothing was wrong with it.

 

Welcome to the forum

What is the exact code or codes?

You have a dual spark plug system, both spark plugs fire in each cylinder at the same time, no alternating(Myth)
This means the engine can run fine with either coil pack unplugged, these engines used just 4 spark plugs from 1974 to 1988
It will have a little less power but shouldn't misfire, if iot does then you have a bad spark plug or wire, maybe coil pack itself

So unplug 3 wire connector on either coil pack, move connect back so it can't arc to coil
Start engine
Should be smooth no misfires, you can drive it this way if you want

Shut off engine
Now test other coil pack and spark plugs


One of the problems with Dual spark plugs is that you can't tell when a spark plug starts to go bad
You only find out when BOTH spark plugs in one cylinder start to go bad, lol

O2 "lean" codes can be caused by misfires, O2 can only see Oxygen(air) in the exhaust, too little oxygen is "rich" to much oxygen is "lean", so not a gasoline thing, its an "air" thing
If a cylinder misfires then NO Oxygen is burned up with the gasoline, and its dumped into exhaust manifold, O2 sensor "sees" that extra "air" and too much air is "lean" code