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[SentraMench]

Hi,

My gf's 96 Sentra 1.6 L sometimes revs up to around 1500 or so
at stop signs (in neutral). It won't kick down. If you drive it to the
next stop sign, the idle will usually be back to normal. Happens when
engine is warmed up.

I already cleaned out the IAC (Idle Air Control valve) with carb
cleaner. Didn't help.

I disconnected the Idle Air Control valve and drove it for 10
minutes and never had a problem. I started it cold ( 40 degrees F),
and drove it til it was hot. No stalling, no high idle !
The check engine light came on, of course.

Is it safe to drive it like this? I would wrap up the hanging
connectors to keep dirt out of them, of course.

A new IAC would cost $170. But why bother getting a new one if the
car runs fine without it, right ?

Thanks

[JM]

I have the same problem with my 99 Altima! I've been trying to find the
cause since I got it but haven't had much luck. I also unplugged the IAC
valve, which stopped the revving at a stop and the idle was down to where I
expect it should be all the time. Mine usually returns close to a normal
idle after a few seconds of high idling when I get to a stop.

Have you tried adjusting the idle speed? There's a procedure you're
supposed to follow, I think it's to unplug the throttle position sensor and
start the car, then set the idle speed by turning the adjust screw until the
idle is around 750. That's the first thing I wanted to do with mine, but my
idle screw seems to be seized.

You'll notice some issues with the IAC unplugged, most notably the engine
will probably stall out if you turn on the rear defrost and the blower at
full blast. Basically any load on the engine at idle will cause it to die.
That was my problem. Also, when starting, mine would want to stall right
away unless I kept my foot on the gas a little until it got itself figured
out.

I came up with a bandaid fix by putting a rubber o-ring into the hose that
runs from the intake to the IACV valve, which limits the amount of air to
the valve... this almost solves the problem, but not completely.

I have had my car to the dealer, where they told me everything is within
spec, with the exception of not being able to adjust the idle screw, so it
may be that simple. Do you know if your gf's car has always done this, or
has it just started recently?

Either way, if you learn anything more, I'd appreciate if you could fill me
in -- and I'll do the same.

[SentraMench]

Hi. Thanks for the reply. With the IAC disconnected, I put the fan on
full blast and it didn't stall it our or even change the rpm. I turned
on the A/C too, and it had no effect on the idle, although the
compressor may not have engaged, since the temp was around 40 F. I'll
try something with a heavier load next time, like the lights and rear
window defogger, and wipers.

I do not have to keep the gas pedal down, ever, to keep the engine
running. Since I started it when cold, I thought I would have to keep
the pedal down, but no.

I have not tried adjusting the idle screw. But I have read that that
can cure an erratic idle.

The car has been exhibiting the occasional the high idle for about 6
months.

I hooked the IAC back up today, and reset the computer, to get rid of
the check engine light, and drove it around quite a bit, to about 30
stop signs, and it never revved up. That's typical. Some days it does,
some days it doesn't.

[Codifus]

SentraMench wrote:

[willshak]

On 11/20/2005 9:46 PM US(ET), SentraMench took fingers to keyboard, and
typed the following:

[JM]

"Codifus" <codifus@optonline.net> wrote in message
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