Hello, I have a 5spd 1998 Ford Ranger xlt, 4x2 2.5 lima. I am getting this mystery miss when the truck is at low idle, Especially after idling down from high idle. The truck has 176k and just started to act weirdly randomly on a warm day. I have owned the truck for the last few months and haven't had any issues aside from replacing the consumables. It doesn't do it all the time but seems to do it no matter if it is warm or cold. I have attached videos showing what it is doing exactly. here is a list of what I have done since owning the truck:

replaced both upstream and downstream o2 sensors (i felt they needed to be replaced as the pigtail wiring started to dry rot)
replaced lifters and valve cover gasket (lifters were a bit noisy)
Replaced Maf (after cleaning the old one and having surging issues)
replaced all intake manifold gaskets (fog tested system afterwards with no leaks visible)
replaced all 8 spark plugs, wires, and both coils (old plugs didn't show any extreme color)
compression tested all cylinders and all tested within 10% of each other with no visible leakdown
replaced differential sensor and egr (truck through a code for egr flowing excessively and they were still the oem units, also blew through egr tube and replaced dps rubber hoses)
replaced battery and alternator
cleaned throttle body cleaned what grounds i could easily see.
tested fuel pressure at 64psi when truck was running.
ohmed out the 1st and 4th injector (couldn't reach the injectors under intake) and both tested at 14.4 ohms
measured the header temps coming off the head at each cylinder and the temps were all within 20-40 degrees of each other

i feel the issue is rpm speed related and clears up when i rev the truck up, would this lead me to believe it is a timing issue (cam or crank pos. sensor) and causing this miss?

 

Welcome to the forum

Just FYI, your 2.5l can run just fine with 1 coil pack unplugged, ran with just 4 spark plugs from 1974 thru 1988 as a 2.3l
The extra set of spark plugs was added for more power

But you can use that ability for testing
Unplug the 3 wire connector for either coil pack, make sure its moved back far enough to avoid arcing
Start engine
See if there is a more notable misfire
Go for a drive, there will be slightly less power, but just a test to make sure all 4 spark plugs are work as they should

Then reverse it, use the other coil pack on its own

Benefit of dual spark is more power
Drawback is, its hard to tell if one spark plug is not working like it should, lol