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The defroster is just the heater pointed at the windshield. It shouldn't have anything to do with the idle unless maybe it's using too much power for some reason and the alternator can't keep up.

John
 

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Hahahaha, It's a FORD my friends, everything is going to be okay.

ALL FORDS late 1970's on up, actuate the AC compressor when in ANY defrost mode on the dash switch.

That is the power fluxuasian you are feeling. There should be a solenoid on your throttle body that bumps the idle up while it's in AC mode which includes the defrost position. If yours does not, then you simply need a tune up to make the engine run a little better with the AC compressor on.
 

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I have a 2003 ranger and when I'm running the defroster the engine idle drops then goes up when I'm stopped and in gear.Any help would be appreciated.
Sounds normal. Has this just begun or has it just become noticeable?

With the defrost on, the AC compressor is energized putting a load on the engine. The ECM/PCM picks this up and sends a signal to the IAC motor to increase the RPM when under this load. If your idle only goes up noticeably at a stop, it sounds normal. Otherwise, start by scanning for codes.
 

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What FE said+ . It is probably your IAC valve getting gunked up and not responding fast enough to compensate for the increased load when the AC compressor engages. Remove the IAC and clean it with some non clorinated brake cleaner. If this improves the idle, replace the IAC.
 

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Discussion Starter · #6 ·
Alot of good advice.I checked the freon pressure and it was alittle low.Tha compressor was coming on then shutting off,and maybe this is causing the trunk to idle funny.I added a can and it's still doing the same thing. What is the IAC valve? I will check that next.
 

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Alot of good advice.I checked the freon pressure and it was alittle low.Tha compressor was coming on then shutting off,and maybe this is causing the trunk to idle funny.I added a can and it's still doing the same thing. What is the IAC valve? I will check that next.
compressor going on and shutting down is normal ...
it does that when it reaches a surtain pressure...when pressure drops it will go on again...
(IAC) idle air controller valve....

Your IAC is mounted to your engine's upper intake near the throttle body...
read this thread..
Idle Air Control Valve - Ford Truck Enthusiasts Forums
 

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If you don't have any video with sound of your issue, I fully believe you will be wasting $66 bucks.
Sounds cheap to me. Good thing he doesn't need that idle solenoid for an EFI TB you suggested. I hear they are no longer produced... :frown:

Simply put, the IAC motor has to be serviced regularly (along with the TB) as it is subject to PCV fumes. FORD offered a set-off kit at one time but it was not a sure cure.
 

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You FOOL, I never suggested he get an idle solenoid! Read my goddamn words before jacking off in your reply.

I said exactly this!
There should be a solenoid on your throttle body that bumps the idle up while it's in AC mode which includes the defrost position. If yours does not, then you simply need a tune up to make the engine run a little better with the AC compressor on.
slow down and read pal. Like I told him. it is 100% NORMAL for ALL Fords built after the early 70's to Activate the AC compressor when the heater control knob in DEFROST mode. (Unless the Ford does NOT have AC....)

If there is NO solenoid, it's Compensated by the IAC motor and controlled by the computer, but that STILL is NOT an indication of the IAC motor going bad!

With some hands ON knowledge of these things you'd have grasped that factoid very quickly!!!!!
 

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Discussion Starter · #12 ·
Ok I'll try a tune up.It only does this when the ac or the defroster is on,but this morning when I drove to work with the ac and defroster off,when I stopped and put the truck in park,the idle dropped to the point were the truck almost stalled?
 

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You FOOL, I never suggested he get an idle solenoid! Read my goddamn words before jacking off in your reply.
Do you ever post without calling others names?

I said exactly this! slow down and read pal. Like I told him. it is 100% NORMAL for ALL Fords built after the early 70's to Activate the AC compressor when the heater control knob in DEFROST mode. (Unless the Ford does NOT have AC....)
Below is what you posted-

ALL FORDS late 1970's on up, actuate the AC compressor when in ANY defrost mode on the dash switch.

That is the power fluxuasian you are feeling.

There should be a solenoid on your throttle body that bumps the idle up while it's in AC mode which includes the defrost position.

If yours does not, then you simply need a tune up to make the engine run a little better with the AC compressor on.
You implied that there was a solenoid. This would cause the original poster to go out and look for an electric motor which hadn't been used since CFI.

And no, a simple tune-up will not mask the symptoms of a bad IAC.

You are simply a liar Gary. You will do and say anything to cover your a$$. It is lack of character and not fully any fault of your own.

With some hands ON knowledge of these things you'd have grasped that factoid very quickly!!!!!
I have extensive hands-on. And I didn't say the IAC was at fault. Another poster jumped on that song and dance.

If you would stop and think before you hit the reply button attempting to be cute with your butt buddies here, you wouldn't need to get yourself all fired up and pull an OBAMA.
 

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Ok I'll try a tune up.It only does this when the ac or the defroster is on,but this morning when I drove to work with the ac and defroster off,when I stopped and put the truck in park,the idle dropped to the point were the truck almost stalled?
Service the IAC and check basic curb idle RPM.
 

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Do you ever post without calling others names?

Below is what you posted-
I saw what I posted kul, but YOU misread what I WROTE
You implied that there was a solenoid. This would cause the original poster to go out and look for an electric motor which hadn't been used since CFI.
did NOT imply that. but I DID fail to mention that it's computer controlled through the IAC motor, WHICH my dearest friend, is NO REASON to REPLACE the IAC motor!
And no, a simple tune-up will not mask the symptoms of a bad IAC.
no they will not, but they WILL ensure a good foundation for a diagnosis!
You are simply a liar Gary.
calling me a liar will get your lip fattened!
You will do and say anything to cover your a$$. It is lack of character and not fully any fault of your own. [\quote] I got more character in my thumb than you do in your entire body pal. I don't tell folks that buying a $66 dollar item will likely fix their problem if there are other things to be tested cheaper and first!
If you would stop and think before you hit the reply button attempting to be cute with your butt buddies here, you wouldn't need to get yourself all fired up and pull an OBAMA.
I get fired up when you are a dikweed. If this guy keeps having issues I will and CAN go there and show him how to clean his IAC, and change it should it fail to work properly, and show him hot to test the voltages going to and from the IAC motor. What can you do?

I do not post to attempt to be cute. I am a natural beauty.
 

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You FOOL, I never suggested he get an idle solenoid! Read my goddamn words before jacking off in your reply.

I said exactly this! slow down and read pal. Like I told him. it is 100% NORMAL for ALL Fords built after the early 70's to Activate the AC compressor when the heater control knob in DEFROST mode. (Unless the Ford does NOT have AC....)

If there is NO solenoid, it's Compensated by the IAC motor and controlled by the computer, but that STILL is NOT an indication of the IAC motor going bad!

With some hands ON knowledge of these things you'd have grasped that factoid very quickly!!!!!
laughing at you FE , trying to be like the moron klutz ?

no understanding of what you post
 

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Do you ever post without calling others names?

Below is what you posted-



You implied that there was a solenoid. This would cause the original poster to go out and look for an electric motor which hadn't been used since CFI.

And no, a simple tune-up will not mask the symptoms of a bad IAC.

You are simply a liar Gary. You will do and say anything to cover your a$$. It is lack of character and not fully any fault of your own.

I have extensive hands-on. And I didn't say the IAC was at fault. Another poster jumped on that song and dance.

If you would stop and think before you hit the reply button attempting to be cute with your butt buddies here, you wouldn't need to get yourself all fired up and pull an OBAMA.
klutz , you should like mitt r , he likes wind jobs and you like blowing smoke to hide your stupidness
 

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Damn FE, Have you been drinking over at dans house? I sugested that he CLEAN the IAC. Then if that improves the idle consider replacing the IAC. BTW I do have hands on experiance with this and have seen it work many times. It is not the only thing that can cause idle problems, but it is the first place I would look when the idle is dipping to low.

To the OP.
Try cleaning the IAC valve it is a 10 min job. The throttle blade on a FI engine closes far enough that it will not run without the IAC valve open.
 
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