98 Explorer - Cold Starting/ Idle Problem

My 98 Explorer will not remain in idle after a cold weather start. It turns
over fine and initially goes up to a fast idle, but slowly drops off to a
stall. I am required to feather the pedal at a 3000+ RPM range to warm the
engine before it will idle on its own. Problem disappears once the engine
is warm, and is never a problem in warm weather. No associated 'check
engine light'. I service normally (oil every 3-4k) and follow mx book for
mileage checkups. Last checkup 8k miles ago at 64k (unfortunately during
the summer months when the problem is non-existent). Is this a known Ford
problem? Anyone familiar with this? Any suggestions? I told the dealer
mechanic about the problem at the 64k checkup, but the problem still
exists...don't even know if he looked into it. Being a WI resident, the
problem exists for about 5 months per year. Thanks in advance for any help.
Am planning to bring it in to a mechanic once I have a bit more info
available to me.

j urb

tj wrote:
>
> My 98 Explorer will not remain in idle after a cold weather start. It turns
> over fine and initially goes up to a fast idle, but slowly drops off to a
> stall. I am required to feather the pedal at a 3000+ RPM range to warm the
> engine before it will idle on its own. Problem disappears once the engine
> is warm, and is never a problem in warm weather. No associated 'check
> engine light'. I service normally (oil every 3-4k) and follow mx book for
> mileage checkups. Last checkup 8k miles ago at 64k (unfortunately during
> the summer months when the problem is non-existent). Is this a known Ford
> problem? Anyone familiar with this? Any suggestions? I told the dealer
> mechanic about the problem at the 64k checkup, but the problem still
> exists...don't even know if he looked into it. Being a WI resident, the
> problem exists for about 5 months per year. Thanks in advance for any help.
> Am planning to bring it in to a mechanic once I have a bit more info
> available to me.

Often cold idle problems are related to the IAC (Idle Air
Control). This is cylindrical item attached to the intake
manifold by two screws through a flange on the side of the
cylinder. It will have an electrical connector on the rear
of the cylinder. You can remove it and clean it and see if
this corrects the problem. Or you can just replace it
(~$75).

Ed

It may be the IAC valve as posted in the other response, but in all
likelihood I'd say your manifold (either upper or lower) gaskets are
leaking. If you had work previously done on the front timing chain and
tensioner, they should have replaced the lower intake manifold gaskets.
Even so, there is no guarantee on the quality of the work. The cold idle
problem still existed on my 98 Explorer because the guys at the dealership
failed to torque the upper manifold to the lower manifold. Found this out
when I replaced the lower manifold gaskets myself because the dealership
didn't want to do the job again since they said they did it right! Problem
solved. BTW - this mostly applies to the 4.0 SOHC engine.

"tj" > wrote in message
...
> My 98 Explorer will not remain in idle after a cold weather start. It
> turns over fine and initially goes up to a fast idle, but slowly drops off
> to a stall. I am required to feather the pedal at a 3000+ RPM range to
> warm the engine before it will idle on its own. Problem disappears once
> the engine is warm, and is never a problem in warm weather. No associated
> 'check engine light'. I service normally (oil every 3-4k) and follow mx
> book for mileage checkups. Last checkup 8k miles ago at 64k
> (unfortunately during the summer months when the problem is non-existent).
> Is this a known Ford problem? Anyone familiar with this? Any
> suggestions? I told the dealer mechanic about the problem at the 64k
> checkup, but the problem still exists...don't even know if he looked into
> it. Being a WI resident, the problem exists for about 5 months per year.
> Thanks in advance for any help. Am planning to bring it in to a mechanic
> once I have a bit more info available to me.
>
> j urb
>

The manifold gasket was a problem on many of the 98's. I had the problem on
my 98 but the symptoms were somewhat different. In my case the car would
idle up and then cycle up and down. It would not drop low enough to stall.
Your leak might be worse than mine was.

HTH
Steve
"Xx" > wrote in message
news:GX4Xd.54773$t46.44173@trndny04...
> It may be the IAC valve as posted in the other response, but in all
> likelihood I'd say your manifold (either upper or lower) gaskets are
> leaking. If you had work previously done on the front timing chain and
> tensioner, they should have replaced the lower intake manifold gaskets.
> Even so, there is no guarantee on the quality of the work. The cold idle
> problem still existed on my 98 Explorer because the guys at the dealership
> failed to torque the upper manifold to the lower manifold. Found this out
> when I replaced the lower manifold gaskets myself because the dealership
> didn't want to do the job again since they said they did it right!
> Problem solved. BTW - this mostly applies to the 4.0 SOHC engine.
>
> "tj" > wrote in message
> ...
>> My 98 Explorer will not remain in idle after a cold weather start. It
>> turns over fine and initially goes up to a fast idle, but slowly drops
>> off to a stall. I am required to feather the pedal at a 3000+ RPM range
>> to warm the engine before it will idle on its own. Problem disappears
>> once the engine is warm, and is never a problem in warm weather. No
>> associated 'check engine light'. I service normally (oil every 3-4k) and
>> follow mx book for mileage checkups. Last checkup 8k miles ago at 64k
>> (unfortunately during the summer months when the problem is
>> non-existent). Is this a known Ford problem? Anyone familiar with this?
>> Any suggestions? I told the dealer mechanic about the problem at the 64k
>> checkup, but the problem still exists...don't even know if he looked into
>> it. Being a WI resident, the problem exists for about 5 months per year.
>> Thanks in advance for any help. Am planning to bring it in to a mechanic
>> once I have a bit more info available to me.
>>
>> j urb
>>
>
>

When my IAC started going bad I didn't notice it until the Fall when the
weather started getting colder. First symptom was that it took longer to
"catch" than normal when starting, but would idle ok after the engine warmed
up. After a couple of weeks (maybe a month) it got to where it wouldn't
start and idle on it's own without holding the throttle open. I ended up
cleaning the IAC valve soon after it got to that point, so I don't know if
the problem would have gone away once the weather warmed up. My first
"cleaning" lasted a couple of years (I used a throttle body cleaner that was
marked safe for coated throttle plates). When it started having problems
again I figured it was already on "borrowed" time and tried cleaning it
again. I think I overdid it the second time because afterward it started
making a trumpeting noise at idle (but it was a smooth idle :-). Replaced it
a couple days later a new one from O'Reilly's and that cured the trumpet.
Real easy to replace on my '96 OHV V6.

Steve


"tj" > wrote in message
...
> My 98 Explorer will not remain in idle after a cold weather start. It
turns
> over fine and initially goes up to a fast idle, but slowly drops off to a
> stall. I am required to feather the pedal at a 3000+ RPM range to warm
the
> engine before it will idle on its own. Problem disappears once the engine
> is warm, and is never a problem in warm weather. No associated 'check
> engine light'. I service normally (oil every 3-4k) and follow mx book for
> mileage checkups. Last checkup 8k miles ago at 64k (unfortunately during
> the summer months when the problem is non-existent). Is this a known Ford
> problem? Anyone familiar with this? Any suggestions? I told the dealer
> mechanic about the problem at the 64k checkup, but the problem still
> exists...don't even know if he looked into it. Being a WI resident, the
> problem exists for about 5 months per year. Thanks in advance for any
help.
> Am planning to bring it in to a mechanic once I have a bit more info
> available to me.
>
> j urb
>
>

I have the exact same problem. Was curious if yours is accompanied by a
high pitched noise (vaccum leak) as you press/release the gas pedal on
smooth hiway. Mine also exhibits this problem, so i thought the two
might be related as the other posts also mentioned a vaccum leak.

Mine didn't make any noise until I messed it up with my second "cleaning",
and even then it was only at idle, until I opened the throttle a little - it
sounded more like a horn than a high pitched noise. However, when it's
fairly cold out I do have an intermittent high pitch squeal sound until
warm-up, and that varies with throttle opening - usually at about cruising
speed on the highway. It doesn't do it all the time, just when the air is
pretty cold, and it goes away once the engine is warmed up. When I took it
in for that a couple years ago the dealer said it was "throttle plate
whistle", had something to do with the material they make the throttle
bodies out of these days, and I left it at that. It *has* been doing it more
often this winter, so now you've got me wondering if maybe it is some type
of gasket leak that closes up after the engine warms up... Thanks!?!? ;-)

Steve


"inetquestion" > wrote in message
lkaboutautos.com...
> I have the exact same problem. Was curious if yours is accompanied by a
> high pitched noise (vaccum leak) as you press/release the gas pedal on
> smooth hiway. Mine also exhibits this problem, so i thought the two
> might be related as the other posts also mentioned a vaccum leak.
>