04 ranger super cab 4x4 4.0 auto. I have been having problems with ignition to where I have had dash warning lights on with key in pocket. Won't start disconnect battery. Key in on position reconnect positive cable start turn key off still running have to pull breather tube kill engine. This has fixed itself three times now. I'm thinking ECM issues. Now when I start the truck when cold it idles at about 1600 rpm after a few seconds it drops to 1000 rpm. Any suggestions would be greatly appreciated thanks.

 

Reads like the ignition switch under the steering column is not being put into the correct position with the key

Has turning the key ever felt odd, sticky or loose?

The ignition switch is a Slider switch with 4 positions, ACC, OFF, RUN, START

On the end of the key cylinder is a gear, when you turn the key that gear slides an actuator rod that runs down, inside steering column, to the ignition switch and moves it into one of its 4 positions

It could be the ignition switch is worn out or loose, but could be the actuator rod as well, which is hard to change
Ignition switch is fairly easy to get at and remove to check it, and you can also then check if actuator rod feels loose

Video here on getting out ignition switch: youtube.com/watch?v=j3I2oye8OpQ
Disconnect battery FIRST!!

Once its out you can reconnect ignition switch to its wiring and battery, then test the OFF and RUN positions as far as dash lights coming on and going off, and you can start it as well, but key need to be in the slot for the PATS to allow startup



Depending on outside temp Cold start should REV to 1500+ RPM and then start to drop down, 1,100 if 40-60degreeF, higher if lower temp, if it didn't do this before then something was wrong then, its corrected itself now
Then as engine coolant warms up it should drop gradually to about 800rpm for automatic, 700 for manual trans
If it not dropping RPMs down then I would clean the IAC Valve first, and maybe replace ECT sensor, not sender, sensor

 

Thanks for your reply. I have already replaced the ignition switch and has not fixed the problem. At the moment the truck seems to be running fine, but I never know when it will act up. I am completely baffled as to the warning lights and not shutting down because whenever it happens nobody is even near the truck.

 

Wife had a car that would do the same thing, very random and unpredictable.
Took forever to figure out that it only happened when she had the tilt steering wheel all the way up.

Properly adjusted ignition switch and cured it.

 

Yes +1 ^^^ most likely the actuator rod then, if you replaced ignition switch

What did you find wrong with ignition switch?
Was it loose or tight?
Or did you just replace it?


The ignition switch sends power to the fuses in the cab fuse panel that powers the dash warning lights, that's their only connection to power, there are no relays or wiring that by pass ignition switch, everything depends on it being in correct position, OFF or RUN

Simplified image of how actuator rod works: https://cimg7.ibsrv.net/gimg/www.for...e1343a526d.gif

If gear is not tight then ignition switch doesn't move to correct position every time, can come and go

 

Thanks alot, I will definitely check check the actuator rod because when I got the truck the shift indicator never matched up with the letters on the dash. There is a small gear that you can adjust to line them up so that's what I did. I wondered why it was so easy.