Just bought my 06 F150 and really like it....4.6 supercrew 4x2 w/49,000 miles

However,when I start it when cold out (it's been cold here) it idles about 1500 rpms. It seems to take forever to idle down to under 1000 rpms. Is this normal?

I am concerned about shifting into D or R with the engine idling that high...seems to jerk into gear, but then immediately is ok

Once it is warm, I can start it and it stays around 700 rpm or so.

Any issues here??

 

It sounds normal to me, sometime if it's cold out, it may take a while (maybe 15-20 seconds) to drop down out of high-idle. The ECU is just trying to allow the temp to climb up a little to ensure proper combustion when it drops down to normal idle.

 

Correct me if I'm wrong but I believe the high idle it to light off the catalytic converters in order to meet LevII tailpipe emissions.

 

That's probably more a more likely reason for the high-idle, but most cars I've owned have a high-idle setting when cold to help with dying/stumbling issues that arrise if low-idle is used.

 

If it only took 15-20 seconds, it would be ok....I let it run almost 6 minutes yesterday (32 degrees) before it idled down under 1000 rpms....seems like a long time to me. My wife 06 Edge only takes about a minute to idle down under 1000 rpms....I dunno

 

Normal.

 

Normal!!! Mine does it to...everymorning.

 

Thanks for the feedback, guys....glad all is well.

 

Hear is how the cold start stratigy works.
At time of starting, the PCM looks at the values of the cylinder head temperature and the intake air temperature resistance values.
These values set the IAC open, adjust the ignition timing and fuel injection amount all for high idle and cold idle speed.
Sometimes if the temperature is low enough a software timer will control the idle return to hot idle specs.
All this is to be sure cold driveaway can be done without hesitation and to heat the cats and OX sensors to 600° +/- to begin their control of fuel at the earliest time.
.
Idle speed control: The PCM uses the crank position sensor as the tach for detecting crank speed.
In the PCM program is a table set with the idle rpm to match the spec.
The PCM looks at the RPM and tries to match the table value to within +/- 50 rpm by contunious adjustment of the IAC to control air into the motor.
As well the ignition timing changes with conditions.
.
Issues: If the IAC function becomes sluggish for any reason, the idle will act intermitttant, cold start problems are likely etc.
Bottom line is there is a lot more going on for what seems like a simple action.

 

^ An 06 does NOT have an IAC.

 

Old IAC or new electronic throttle plate control, it works the same way.

 

this is not normal, my truck used to do it, there is a tsb out for it and you need to bring it to a dealer to update your pcm, after that my truck hasnt done it since, i will try to copy and paste from the fordtechservice dealer connection website to show you the tsb

 

^ Never heard of this. Mine still does it when it is really cold, and that is after the tune.

 

mine does it almost everytime is start it,pretty annoying for me

 

all im saying is when i got the latest ford pcm update, my high idle problem went away