Question about 2000 Ford Ranger SuperCab
Hello... The first thing to determine is whether the high idle is caused by a mechanical issue, such as a faulty idle air control sensor (IAC), or a throttle plate that is not closing, or if the idle speed is actually being commanded high by the computer. One of the easiest ways to do that is to simply unplug the IAC with the truck at idle, and allow the engine to slow to the "minimum air rate" or base idle speed. There is no published spec, but if your minimum idle speed is in the 500-600rpm range in park, thats close enough. There is no normal service adjustments required, but if something is keeping the throttle plate from closing, then you'll have to correct that.
Now...when you unplug the IAC, you will find either a normal minimum idle, or no change at all. If there is no change, and the throttle is not sticking open, suspect air is getting around the throttle plate, which could be a bad IAC, because thats exactly what it does, it allows air to enter the engine around the throttle plate. Normally the computer has complete control of the IAC, but it can fail mechanically, so it must be checked.
The next scenerio would be the idle speed being correct when the IAC is unplugged, and then going back up when it's plugged back in. This would indicate the computer is actually commanding the idle speed high....and this is where the correct scan tool becomes so important, because it allows the techincian to see this information right from the computer. From this info the problem can be determined and repaired.
Good luck..i hope this helps...please take time to rate me a fixya.
Posted on Jul 23, 2009
Low / uneven idle problem can cause by a lot of components.
Dirty air filter
Dirty injectors + o-rings
Vacuum leak at intake manifold and vacuum hose.
Bad Idle Air Control Motor (IAC)
Low compression (170 psi + is OK)
Start cleaning and repair these trouble spots and see is there any improvement.
For more advance DIY'er then you may try this.
Use a can of Berryman carburetor clean to locate the vacuum leak.
SEE SAMPLE PICTURE HERE
This is a 20-30 minutes job.
Vacuum leaks can occur in following locations.
Intake manifold AND/OR vacuum lines.
Intake manifold is not accessible unless the engine head if off.
You can still check the potential leak by spraying some Berryman near the intake manifold.
Listen for rpm increase after you introduce the Berryman (FUEL) at idle.
Do the same starting from the brake booster unit (the round unit) on the drive side fire all.
Carefully listen for increase of RPM right after to spray the Berryman to the potential vacuum spot.
Get a friend to HEAR the ROM increase or monitor for RPM on the tech.
DO NOT AIM the Berryman into any heat source.
PLEASE RATE my answer if it is useful to you.
Posted on Dec 14, 2009
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Dec 03, 2016 | Mercury Cars & Trucks
Mar 15, 2015 | 2000 Nissan Frontier
Mar 16, 2014 | Acura Cars & Trucks
Dec 24, 2010 | 1988 Volvo 740
Mar 12, 2010 | Hyundai Motor 2003 Elantra
May 15, 2009 | 1993 Ford Ranger SuperCab
Jul 16, 2008 | 1999 Jeep Cherokee
190 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: