86 GT 5.0 Idle Question

I have a 1986 Mustang GT 5.0 with the five speed manual trans. After warm
up and when idling, the engine idle speed "surges" (ie. it varies up and
down, slightly, but noticeably).

Anyone had any experience with this, what is the matter and what I might do
to correct it?

Thanks a bunch.

Larry

I think a surging idle has been addressed in this group 100 times. Do a
search on it. 86 is EFI? Sounds like the air intake and any sensors in it
needs a good cleaning.

Brad

"LR" > wrote in message
news:uMhmh.5291$5q6.4143@trndny02...
>I have a 1986 Mustang GT 5.0 with the five speed manual trans. After warm
>up and when idling, the engine idle speed "surges" (ie. it varies up and
>down, slightly, but noticeably).
>
> Anyone had any experience with this, what is the matter and what I might
> do to correct it?
>
> Thanks a bunch.
>
> Larry
>

LR wrote:
> I have a 1986 Mustang GT 5.0 with the five speed manual trans. After warm
> up and when idling, the engine idle speed "surges" (ie. it varies up and
> down, slightly, but noticeably).
>
> Anyone had any experience with this, what is the matter and what I might do
> to correct it?
>
> Thanks a bunch.
>
> Larry

That sounds like the idle air bypass solenoid and throttle body need to
be cleaned out.

The IABP solenoid mounts to the side of the throttle body. You can
unbolt it (disconnect wiring harness) and clean it out with a cleaner.
At the same time clean out the throttle body and the holes that go into
where the IABP solenoid mounts.

Oh yeah, don't tear the gasket...

Steve
72 Skylark Custom455

LR wrote:
> I have a 1986 Mustang GT 5.0 with the five speed manual trans. After warm
> up and when idling, the engine idle speed "surges" (ie. it varies up and
> down, slightly, but noticeably).
>
> Anyone had any experience with this, what is the matter and what I might do
> to correct it?
>
> Thanks a bunch.
>
> Larry

My car did the same thing; cleaning the IAC fixed it.

http://www.muscularmustangs.com/iac.php

Good luck,
John

A Guy Named Steve wrote:
> LR wrote:
>> I have a 1986 Mustang GT 5.0 with the five speed manual trans. After warm
>> up and when idling, the engine idle speed "surges" (ie. it varies up and
>> down, slightly, but noticeably).
>>
>> Anyone had any experience with this, what is the matter and what I might do
>> to correct it?
>>
>> Thanks a bunch.
>>
>> Larry
>
> That sounds like the idle air bypass solenoid and throttle body need to
> be cleaned out.
>
> The IABP solenoid mounts to the side of the throttle body. You can
> unbolt it (disconnect wiring harness) and clean it out with a cleaner.
> At the same time clean out the throttle body and the holes that go into
> where the IABP solenoid mounts.
>
> Oh yeah, don't tear the gasket...
>
> Steve
> 72 Skylark Custom455
>


Well, well. Look what the Skylark drug in... :-P

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