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Low idle in Drive

Old Mar 18, 2024 | 07:53 AM
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Default Low idle in Drive

Hi,

I have a 1999 LS1 with a 4L60E transmission. Its a drive by cable throttle. I've adjusted the idle to around 800 rpm by adjusting the nut on the cable bracket next to the throttle body. This seems fine when its in Park or Neutral. However, when in Drive the idle drops to around 600 rpm. Is this normal? Could the IAC be dropping the idle down? If so, is there a way to set the idle to 800 rpm ?

Cheers,
Greg
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Old Mar 18, 2024 | 12:49 PM
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Stock idle rpm for all years LS1 F-bodies is: M6: 800rpm. A4: 650rpm (park/neutral), 550rpm (in gear) The stock tach is off 150rpm or so.
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Old Mar 19, 2024 | 06:11 AM
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Originally Posted by carmodyg
Hi,

I have a 1999 LS1 with a 4L60E transmission. Its a drive by cable throttle. I've adjusted the idle to around 800 rpm by adjusting the nut on the cable bracket next to the throttle body. This seems fine when its in Park or Neutral. However, when in Drive the idle drops to around 600 rpm. Is this normal? Could the IAC be dropping the idle down? If so, is there a way to set the idle to 800 rpm ?

Cheers,
Greg
Is it so low it’s dying? Every auto that I’ve ever driven idles lower in gear than it does in park.

Cheers

Cliff Claven
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Old Mar 19, 2024 | 08:02 AM
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No its not dying. Just trying to keep the idle up so there's a bit more oil pressure at idle. Sounds like its normal behaviour.

Cheers,
Greg

PS> if I set the idle higher when in Park, will I get a higher idle in Drive, or is it purely a function of the IAC and the ECU as to what te idle is set to in gear?


\\
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Old Mar 19, 2024 | 08:55 AM
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If you set your base idle higher with the screw, I think your "in drive" idle will be a bit higher as well.
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