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Discussion Starter #1
My car's battery and alternator were both replaced a year ago (by the previous owner), I have the receipt.

The problem is that when the A/C is on, or when I press the power window buttons, the car's RPM goes up a little bit as if to compensate for the load. Right before doing this, you can see the lights dim a little.

The battery's voltage is at around 12.5 with the car off, when I put max load on it (AC, windows, lights) it drops to 11.5 or so. With the engine on, it behaves the same. Though the voltage is 14.3 but there's still a drop in voltage to 13.5 more or less.

Only other "electrical" issue I have is the fuel gauge not working, despite the sending unit being fine (tested). I guess I have to test the wires to sort this one out.
 

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^^+1 with Automender
Sounds like the IAC may be a touch sticky/slow, everything else in the description sounds normal. A thorough cleaning might be in order, if replacement is necessary fo Motorcraft only, aftermarket IACs are a nightmare.
 

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Discussion Starter #6
Nope, it's gas. Sorry for not specifying.


I'm gonna try to clean up the IAC again and see if it helps.
 

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Nope, it's gas. Sorry for not specifying.


I'm gonna try to clean up the IAC again and see if it helps.

Also put a little oil in the shaft. I carefully push the piston a little to work the oil in. My initial opinion is that it is not OEM unless it has a part # marked some place on it. I will try to look at my 2006 to see if there are any special markings. I believe my 2001s have a Ford part# etched on them.
 

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Discussion Starter #9
Please consider adding your vehicle information to your userpanel, it helps us help you.
Thanks for letting me know, I added my vehicle information to my userpanel.

Also put a little oil in the shaft. I carefully push the piston a little to work the oil in. My initial opinion is that it is not OEM unless it has a part # marked some place on it. I will try to look at my 2006 to see if there are any special markings. I believe my 2001s have a Ford part# etched on them.
Thanks for sharing that, I'll try it out and see if it performs any better. Mine has a part number etched on it, but it's hard to read.
 

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Discussion Starter #10
I cleaned the IAC valve and put some oil on the piston, and I'd say it's a lot better now. The RPM goes up a little with the AC but no dimming, and a single power window barely does anything to the rpm/light dimming. I think it's behaving correctly now. Thanks!
 

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Poor electrical ground can cause this.

Clean your battery terminals and the cable clamps. Also clean the short ground cable that is attached to the inside of
the engine compartment to the battery.
 

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Poor electrical ground can cause this.

Clean your battery terminals and the cable clamps. Also clean the short ground cable that is attached to the inside of
the engine compartment to the battery.
Might I add? See pic, the ground is clamped over paint and rust. Look below and see this eyelet. It is the ground (return) for all the sensors on the engine. I got into this as I had erratic idle speed. The TPS sensor had 5V on one leg, solid but the ground was wandering around so the sensor had erratic position signal. Problem fixed. Location on the firewall pas side.
You can fix this without effecting the PCM memory.


-chart-
 

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