How do I adjust the engine idle speed?

have 2002 Mercury Mountaineer have cleaned MAF and replaced air filter engine fault lights have cleared but engine has high idle speed how do I adjust?

Welcome to this forum! I've moved your thread into the stock 2002-2005 section. Don't play with the set screw adjustment. You might have a vacuum leak or a bad IAC. What were the previous code numbers?

Check for a binding or sticking throttle body. Also, my X had a high idle when it got hot. The hotter the engine got the higher the idle speed. I ended up replacing the IAC with one from Autozone (needed one fast, otherwise I woudl have gotten a motorcraft one). Problem went away.

Double ck the throttle cable, sometimes they wear and stick, closely inspect it down at the gas pedal.

What is the idle speed as indicated by your tachometer?

It is true that there is no idle screw adjustment, as it is computer controlled.

swetrid said:

Double ck the throttle cable, sometimes they wear and stick, closely inspect it down at the gas pedal.

Click to expand...

Curious when did they go to drive by wire? Thanks. imp

imp said:

curious when did they go to drive by wire? Thanks. Imp

Click to expand...

2004.

Thanks for the info got the idea on my motor in the front of it it says engine idle speed I don't make sure an ignition timing or not adjustable pretty basic there but thank you for the input so now my question is it's not idling too high but it is idling low supposed to be at 1 right well it's in the middle now what do I do if I can't touch it what do I do

But again thank you for the input it why was useful

disconnect battery negative cable,use a jump wire from positive on battery to negative cable ( not the battery post ! ) This will clear the computer memory capacitors. hold the jumper there for about 1 minute. Reconnect negative cable. Turn key to ON position,but do not start till it chimes out or about 20 seconds.Start the engine and let idle till normal operating temp, about 10-15 minutes. It will learn it's new idle, then drive normal for it to learn shift points again. It worked for me )

I would clean or change the IAC valve if this doesn't help, but try FREE first )

okay how high is the idle speed? like 1200-1400 rpm or like 2500 rpm?
I ask because
When you clear the codes the truck thinks it is new and is ready to re learn
During this re learn process you might experience a higher then normal idle while the computer figures things out