I have a 2002 ranger edge 3.0 engine 4x4. It idles very high, up around 3000 rpm. If I disconnect the battery cable and let it sit a few minutes then connect it again it idles normal. I have replace the IAC but did not help. What could be the problem? Thanks to everyone in advance.

 

Welcome to the forum

Manual or automatic?

You should only replace factory IAC Valve with Motorcraft or Hitachi brand IAC Valves, other brands can cause same issue
Ford Rangers used a true solenoid IAC Valve, the other brands are a solenoid/stepper IAC Valve

After engine is warmed up and idling high, unplug the 2 wire connector on IAC Valve, it will close
RPMs should drop to 500-600 or engine may even stall, either is good, means no vacuum leaks

But also means the computer was setting the high idle, so software glitch
I assume speedometer works
Engine is not running hot

If so then you may need computer to be re-flashed to get rid of the glitch, Ford Dealer
Resetting computer(unhooking battery for 5 min) clears the Computer memory for IAC Valve operation, so it has to re-learn IAC Valve control
And apparently there is a glitch in that process

You can Call local Ford dealer and give them your VIN, they can look up if there is a later software version to deal with this issue, or if they can even re-load last software, usually they won't have files older than 15 years, but calling is free, lol

And there are no Codes in memory?

 

Automatic No codes. How much does it cost to reflash?

 

Been awhile so prices may have(probably did) change but just ask if they can do it and the price, $100-$150, about 2 hours shop time

 

Ok thanks for your assistance.