Isuzu Rodeo fast idle

[GeeBee]

We have a 1997 Rodeo with the 4.2L V6. It idles too fast. Things we have
done include replacing the "idle motor", which is actually a solenoid.
That only cured it for a short time. I have tried lubricating throttle
linkage and throttle body, to no avail. Strangely, when the battery was
disconnected for an unrelated problem, everything was fine for a few
hundred miles, then the idle speed started to creep up again, to the
point it idles at about 2200 rpm. This is not a good thing considering
we take it up mountain roads occasionally. Even changing down a gear,
the machine wants to run away on long down grades, leading to me having
to ride the brakes way too much.

[Steve W.]

GeeBee wrote:
> We have a 1997 Rodeo with the 4.2L V6. It idles too fast. Things we have
> done include replacing the "idle motor", which is actually a solenoid.
> That only cured it for a short time. I have tried lubricating throttle
> linkage and throttle body, to no avail. Strangely, when the battery was
> disconnected for an unrelated problem, everything was fine for a few
> hundred miles, then the idle speed started to creep up again, to the
> point it idles at about 2200 rpm. This is not a good thing considering
> we take it up mountain roads occasionally. Even changing down a gear,
> the machine wants to run away on long down grades, leading to me having
> to ride the brakes way too much.

Sounds like you have a vacuum leak somewhere. Air AFTER the MAF will
cause a high idle.

--
Steve W.

[Rodan]

GeeBee wrote: (1997 Rodeo 4.2L V6)

It idles too fast. We replaced the IAC and that cured
it for a short time. Lubricating the throttle body parts
does not help. When the battery was disconnected
for an unrelated problem, everything was fine for a few
hundred miles, then the idle speed started to creep up
again, to about 2200 rpm. Even changing down a gear,
the machine wants to run away on long downgrades,
leading to me having to ride the brakes way too much.
__________________________________________________ __________

"Steve W." wrote:

Sounds like you have a vacuum leak somewhere. Air
AFTER the MAF will cause a high idle.
__________________________________________________ _________

Yes, the first thing to suspect is a vacuum leak. Check
the vacuum lines for cracks and tighten throttle body
mounting screws. NOTE: The car previously had the
same problem and a new IAC fixed it. It is possible
that the new IAC is failing.

Good luck.

Rodan.