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Chris (aka-Moose)
Chris (aka-Moose), GMC Technician
Category: GMC
Satisfied Customers: 48626
Experience:  16 years of experience
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How can I lower the idle speed om a 98 2.4 grn am

Customer Question

How can I lower the idle speed om a 98 2.4 grn am
Submitted: 1 year ago.
Category: GMC
Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.

At operating temp in park, what is the idle speed now?

Any warning lights on?

Customer: replied 1 year ago.

it is 8 to 9 hundred. The car does 10 mph in drive when hot with my foot off the gas pedal transmission in drive

Expert:  Chris (aka-Moose) replied 1 year ago.

Thanks for the extra info.

At operating temp in park, what is the idle speed now?

Any warning lights on?

Customer: replied 1 year ago.

The tach has small graduations . I estimate 825 to 850 transmission in park motor warmed in operating temperature.Car will go 10 mph in drive with foot off the gas. Very hard on driveline when shifting into drive.

Expert:  Chris (aka-Moose) replied 1 year ago.

The idle speed spec is 750-900 so your right in the middle and the idle speed is electronically controlled by the computer and the idle air control valve. You can try a new IAC valve but I highly doubt it is going to bring the idle speed down any more. You may also want to clean the throttle body, it could be gunked up and possibly stuck barely open.

This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a ~~~5 STAR EXCELLENT~~~ experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.

Thanks Moose.

Customer: replied 1 year ago.

Using the a/c lowers it . Eliminates drive line bang when it is shifted into park. I need to keep another approach. Can I trick the computer to believe the ac is running

Expert:  Chris (aka-Moose) replied 1 year ago.

The AC lowers the rpm because the compressor clutch is engaged and dragging the engine down. The engine would need a load on it to pull the rpms down, there is not a way to trick it. If you did trick the PCM with out the AC actually on, the rpms would be higher. Are you sure you do not have a pressure issue with your transaxle pressure causing it to harsh engage?

Customer: replied 1 year ago.

The transmission was rebuild back in 2014 using my old transmission and I checked out the garage and met the tranny mechanic before I employed him It could be what your saying . If it is how can it be modified? How to test ??

Expert:  Chris (aka-Moose) replied 1 year ago.

You would need to perform a pressure test on the transaxle as your first step.

If its high then there is a concern with the valve body or pressure control solenoid.

Expert:  Chris (aka-Moose) replied 1 year ago.

Hello again Chris here,

  • I am following up with you to see if you got everything you needed from my answer.
  • I have not heard back from you, so I assume you were not pleased. We're you pleased with my help?
  • If you were not pleased with my help, please let me know by replying so I can help more.
  • This post is coming up on the 7 day mark where it times out. When a post times out, that means it's no longer on my active list (you reply and I may never know it.)

Thanks Chris