Hello,
I have a 2006 Ranger with a 3.0 engine. It starts up fine when the engine is cold, but if i shut it off then restart it, the engine runs rough, wont produce hardly any power and the check engine light blinks. The check engine light has been on for a few months now and no one can seem to pull any codes from it. Might be shorted out somewhere. The guys at the local Ford dealership thought it might be bad spark plugs so I replaced them along with the wires. It didn't fix the problem. I have replaced the temperature sender as well. I checked the coil using the method from this video and it checks out fine. Any suggestions?
Thank you.

 

Pull and clean your IAC valve

 

I pulled it and cleaned it. It did seem to improve the idle. Time will tell if this is what was wrong. Thank you jdbeck38201 for the suggestion.