94 ford ranger w/4.0 lacking power until warm up.

[randy31163]

Hello, my 94 Ranger with 4.0 engine is skipping and lacking power until it gets warmed up. It was lacking power this morning and all of a sudden, it got a burst of energy and got power back. Also, the voltage gauge sometimes is working and sometimes it is pegged all the way to the left like it is either shorted out or not charging. I did replace the battery because advance auto check showed that it needed replaced. Any help would be greatly appreciated.
Thank you, Randy

 

[wynnespeed]

my does a similar thing it skips and bucks but when it warms up its fine....

 

[RonD]

First stop would be here
http://www.therangerstation.com/tech_library/CleanMAF.html

MAF needs to be cleaned on the Rangers, just regular maintenance

An uncommon issue would be the ECT sensor, this sensor tells the computer when engine is cold and when it is warm.
If ECT sensor is telling computer engine is always warm then you would get no CEL and engine would run poorly until it warmed up.
But ECT sensors rarely fail, so test it never replace it.
http://oldfuelinjection.com/?p=28

Another test of the ECT is "Does the engine idle higher when cold and then idle goes down as engine warms up?", if so then ECT sensor is working.
ECT sensor is the only means the computer has to set idle based on temperature.
ECT is a TWO wire sensor, all fuel injected engines use them.
Dashboard temp gauge uses a ONE wire sender, they look similar but are not the same.