Irritating Problem with Idle

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nweatherby

New Member

Apr 3, 2007

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Apr 3, 2007

#1

• Apr 3, 2007

• #1

The car I have is a 1999 Mustang 3.8L. Okay I have had this problem since 30000 miles and the car now has about 115000 miles and nobody can fix it so far. I have noticed that when I drive my car sometimes at idle at a stop light it wants to jump 200-500rpms. This is annoying but not my major concern. The major concern comes from shwne I drive it mostly on the freeway then park it for 15-20 Minutes and come back out and start it up the engine almost wants to stall. This is especially bad when reversing. I also get the rpm surge when I am stuck in traffic for a long time say a wreck on the interstate. I am contemplating buying an ELM5 scanner to help me figure it out. Anyway the things I have done so far is replaced plugs, PCV Valve. Cleaned out throttle body and Idle Air Control. Cleaned MAF Wire very carefully.Checked Throttle Position Setting voltage which was 1.0 a little high. Any ideas on what could cause this and whether I should get the scanner. Thanks all

 

raz54

New Member

Dec 21, 2006

205

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Eureka Ca.

Apr 3, 2007

#2

• Apr 3, 2007

• #2

The scanner won't help unless it's throwing a code though. Do you have a CAI or a stock intake?

 

N

nweatherby

New Member

Apr 3, 2007

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Apr 3, 2007

#3

• Apr 3, 2007

• #3

Stock Intake with K&N

It has a stock Intake with a K&N

 

raz54

New Member

Dec 21, 2006

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Eureka Ca.

Apr 3, 2007

#4

• Apr 3, 2007

• #4

You didn't remove the MAF screen did you? The idle will be very irratic and can die without it.

 

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nweatherby

New Member

Apr 3, 2007

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Apr 3, 2007

#5

• Apr 3, 2007

• #5

No

No I just popped out the sensor and cleaned it gently with a qtip and carb cleaner

 

raz54

New Member

Dec 21, 2006

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Eureka Ca.

Apr 3, 2007

#6

• Apr 3, 2007

• #6

I see you cleaned the IAC but it still could be sticking and that will cause it to run like yours. My nephew was telling me a couple days ago that Fords had a problem with them going bad. They don't cost too much so you may want to try one.

 

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nweatherby

New Member

Apr 3, 2007

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Apr 3, 2007

#7

• Apr 3, 2007

• #7

Yeah

If I was going to replace a part I would probably pick that one first. Just trying to get the cheap stuff out of the way first.

 

2muchtime

Founding Member

Jan 30, 2002

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MA.

Apr 4, 2007

#8

• Apr 4, 2007

• #8

how does the car idle when first started in the morning.
does it high idle like it should 1500rpm for a few minutes till it gets warm.

 

N

nweatherby

New Member

Apr 3, 2007

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Apr 4, 2007

#9

• Apr 4, 2007

• #9

Sometimes

Most of the time if does jump up to probably 1200 rpm for a few seconds then drops back down

 

S

swsixpack

New Member

Aug 13, 2006

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Apr 26, 2007

#10

• Apr 26, 2007

• #10

Same kino problem

I have a 2000 v6 and it has a low idle sometime when stopped. I also burn through coolant. I've heard somewhere that the coolant helps with the idle, is this true? Also is there anything that would cause the low coolant besides a head gasket, I don't feel like going through the work to find thats not the problem. There are no coolant puddles on the ground .

 

2

232Mustang95

New Member

Dec 30, 2006

136

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Oslo, Norway

Apr 27, 2007

#11

• Apr 27, 2007

• #11

swsixpack said:

I have a 2000 v6 and it has a low idle sometime when stopped. I also burn through coolant. I've heard somewhere that the coolant helps with the idle, is this true? Also is there anything that would cause the low coolant besides a head gasket, I don't feel like going through the work to find thats not the problem. There are no coolant puddles on the ground .

Click to expand...

If you got a head gasket issue, the coolant will most likely come out of your exhaust as white smoke.

 

Lsredy2kstang

Look, I'm special, dammit

Nov 29, 1999

2,543

5

0

Woodstcock, Georgia

Apr 27, 2007

#12

• Apr 27, 2007

• #12

Could be the TPS as well

 

2muchtime

Founding Member

Jan 30, 2002

890

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Apr 27, 2007

#13

• Apr 27, 2007

• #13

swsixpack said:

I have a 2000 v6 and it has a low idle sometime when stopped. I also burn through coolant. I've heard somewhere that the coolant helps with the idle, is this true? Also is there anything that would cause the low coolant besides a head gasket, I don't feel like going through the work to find thats not the problem. There are no coolant puddles on the ground .

Click to expand...

the coolant does run through a port in the throttle body, it is to keep the
t.b. from freezing on extremely cold days.. has nothing to do with the way the car
runs..
if your not seeing coolant on the ground..it is either being burnt through the exhaust or filling up the heater core box and getting the passenger floor wet..
otherwise it would be coming out of the vent hole in the heater box which coolant
would still hit the ground..
most likely a head gasket.. you dont have milky looking engine oil do you ??
if not it means its running through the exhaust port (headgasket)..
it could only be one other thing intake manifold gaskets...
does the same theory as a head gasket..it will leak right down through to the cylinder..
these engines are known for head gasket problems up until 2001 when they changed the design/ material of the head gasket..
you need to have a head gasket test done at a shop..they use a tool with liquid
which detects hydrocarbons through the coolant. its cheap and easy to have done.. a motor isnt cheap or easy...so get it done..

 

2muchtime

Founding Member

Jan 30, 2002

890

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Apr 27, 2007

#14

• Apr 27, 2007

• #14

nweatherby said:

Most of the time if does jump up to probably 1200 rpm for a few seconds then drops back down

Click to expand...

replace the idle air control ( IAC )..DO NOT GET ONE AFTERMARKET!!!!!
get it from FORD only... it avoids misdiagnosing the right part..

do not go to autozone..

 

GREENBIOCH

Founding Member

Mar 22, 2002

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In an Igloo

Apr 27, 2007

#15

• Apr 27, 2007

• #15

X2 for IAC valve.....sounds very much like an IAC valve, do you have a KandN filter or CAI of some kind.

these mustangs of ours should come with a bag of IAC replacements, cause they seem to get dirty quite a bit and need replacing.

and if the carb cleaner didn't fix it, get a brand new replacement one.

 

2muchtime

Founding Member

Jan 30, 2002

890

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Apr 28, 2007

#16

• Apr 28, 2007

• #16

exactly ...cleaning the iac doesnt always work.. it does nothing when its an electrical failure..

 

S

swsixpack

New Member

Aug 13, 2006

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May 4, 2007

#17

• May 4, 2007

• #17

Thanks

Thanks for all the help guys. I let you know if any of these work