Hello everyone, I have a cheap cold air intake installed on my 2003 4 liter v6, and I can really feel the boost in power while in drive and going through the gears and it runs amazing there. But idling in park it wants to die and idles really rough. The only way it doesn’t die in park is of the accessories like my fan are on and my lights are on.
Could it be my idle air control valve? From what I’ve read that seems to fix a lot of peoples problems with idling.

 

All fuel injected Ranger came with a Cold Air Intake, 1986 thru 2011, just FYI
3rd party add-ons usually just cause issues, and can NEVER add more power, this was proven in dyno test, but anecdotally they are GREAT add-ons

IAC Valves are often replaced but seldom bad, lol
You can clean you IAC Valve
If you want to replace it use only Motorcraft or Hitachi brand, these are solenoid valve, other are stepper motor and can cause same or other issues

Did you install the CAI or buy the vehicle with it?
If you bought it this way then check to see what brand IAC Valve is on there now, previous owner may have swapped it with 3rd party, and thats what is causing the issue

The last part "the accessories like my fan are on and my lights are on."
This could mean your alternator has an issue, voltage regulator inside it is not responding and voltage is dropping to low until demand increases
Test battery voltage engine off, 12.3v to 12.8volts is acceptable
Start engine
Test battery voltage again, 13.5v to 14.8volts is acceptable
Turn on the fan to HIGH and head lights on, should see same voltage as with these OFF

Voltage should never drop below 13.5v engine on

 

Yep.
Aftermarket CAI kits for the V6~4.0L~SOHC are ripoffs & waste of money+time; might give you bragging rights amongst ignorant friends.
Take three Hundred$ bills, set them on fire, enjoy the warmth for a couple of minutes; does you more good than a CAI kit.
Click for info on my V6~4.0L~SOHC AirIntake "ExtremeCheeseBox" Experiment.