New Stalling issue...

coleman

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Ok, my car is stalling when idling even when warmed up.
My car used to stall before it warmed up, but almost never after.
But my EGR lines were corrected :bash: & I hadn't had any problem until just recently.

Anyway, my RPMs are around 750 & dip down around 500 or below & tries to recover.
But sometimes it'll just stall.
What could be the cause?

Idle Air Controller (IAC)? ... what symptoms?
Vacuum lines? ... my vacuum drops just before it stalls, but that may simply be a result of the lower idle speed.
Alternator? ... there is not voltage gauge, so i'm not sure. maybe at low RPMs it isn't charging enough to keep the car running.
 

Jpjr

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well i assume since you've been on here a while that you know about the 'stall' tsb. i've had my ecm reflashed for the 'stall' fix. but yours sound like it may be more mechanical. i usually troubleshoot by first elminating 'spark'.. and then 'fire'.

spark- battery, alternator, plugs, plug wires.

fire- fuel filter, pump, injectors

assuming you have an '04 or have already gotten the re-flash.. i would check your fuel filter. but crap i'm no expert either..
 

Jerryk

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Coleman, clean the Mass Air Meter hot wire element with electrical contact cleaner. You can remove the IAC and clean it (on the old 5.0's.. these probably aren't that much different) with brake cleaner. Try those first. After doing that if it persists, raise the idle to 800 and then 850 if necessary and recheck the TPS voltage not that I fully understand the implications of TPS on the newer cars.
 

05 Roush

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First, check your throttle plates and see if they're sticking. Then replace the IAC.
 

05 Roush

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Also, rotate your spark plugs. Mine used to do the dipping idle and found out it was a loose spark plug in one hole and another one that was having problems with the COP.
 

coleman

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I'm going to try to clean my MAF again...
Worked great the first time I did it, but that was only two weeks ago!
Maybe a bunch of oil is getting into my intake from the valve covers & fouling up my MAF.

What about this IAC? Would the car stall if it's not functioning correctly?

I'll try a few of these items & post some results tomorrow.
 

05 Roush

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Originally posted by coleman
What about this IAC? Would the car stall if it's not functioning correctly?

Absolutely. That was the problem I was having as well.
 

oldmodman

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I just repaired a friends 2000 GT with the same problem. Removed and cleaned his IAC with carb cleaner and a Q-tip. Now runs perfectly. Problem was as you described. It would idle along then RPM would dip and engine would die. And it would not re-start unless you held the throttle open slightly. Perfect after cleaning. I had previously had the same problem on my Explorer and cleaning the IAC fixed the idle problem on it.
 

coleman

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PlatinumCobra & oldmodman ... sweet! I hope that's the problem & a simply cleaning may correct it.
 

coleman

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Ok, I cleaned out the IAC & it didn't help. It was dirty, so now it's clean, but the car was still stalling at times.

So, I decided to play around a little & noticed that the car idles much better without the A/C on. In fact, I think the A/C is somehow causing my car to stall.
When does the compressor kick on? Should it put such a strain on the car @ idle to cause it to stall?
Am I simply too low on freon or could it be a bad compressor?

I know my idle should increase w/ the A/C on, not fluctuate w/ the compressor kicks on like it's doing.

In fact, I took a short drive w/ the A/C off & the car felt great.
 

fordracing19

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What is your base idle with the iac unplugged, assy off with the eng hot? I was having stalling problems after the flash with no codes and called and talked with ford tech line(ford tech). My iac % was at 48 and should be around 38-40. My car would not stay running when i unplugged the iac and let it come down to an idle. Bumped the idle set screw to keep base idle at 500-550 and the iac % went to 40% and has not stalled once and idle doesnt surge.
 

05 Roush

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Originally posted by coleman
I know my idle should increase w/ the A/C on, not fluctuate w/ the compressor kicks on like it's doing.

In fact, I took a short drive w/ the A/C off & the car felt great.

Sounds like a problem with your compressor. Disconnect the clutch wire from the A/C, then turn on the A/C and see if the car dies. If it doesn't it's the compressor.
 

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