1987 S10 6cyl idle wont drop down

Question edited for clarity.
Question moved from Honda Motorcycles.

help in the link

https://www.google.com/search?q=1987+honda+civic+carb+choke+operation

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There are a lot of factors that can cause a poor/no idle problem. I'm guessing the 2.8 lt motor? One common problem on this motor was a bad intake manifold gasket causing an internal vacuum leak supplying the vehicle with unmetered air. The vehicle would idle very poorly and stall. Another problem could be with the IAC ( Idle air control) motor that controls idle. It could be sticky/defective and will not properly control idle. A dirty throttle plate can also cause idle problems as it upsets minimum airflow. You can start by inspecting the throttle plate for dirty/coking and clean with carb spray as necessary. You can also try removing and cleaning the IAC motor pintle or replacing the motor with a known good oneto see if it corrects the problem

need to clean the idle jet out in the carb. you need to take the carb float chamber apart and you will see 2 copper jets. unscrew one jet at a time and clean them out. screw back firm not to tight. wile open clean the filter out of the main fuel line if its black replace with new one or leave to soak in some white vinegar and brush with a old tooth brush put new seal on float chamber and put back on engine. see if its fine then it should be.

Could be the fast idle cam for the choke. When the choke is closed the fast idle cam holds the throttle open until the choke opens.
The cam should be on the opposite side of the throttle cable.

your choke Is stuck on the Injector/carborater. when you press the gas It Is lettIng to much aIr In. check the cable on Injectors or If It Is carb get some carb cleaner from your local automotIve retaIler and take the breather off and spray carb. also check around It to kake sure the cable Is.not streatched nor caught.

The idle screw is on the throttle body near where the gas pedal cable attaches to it. Not sure what sensors it has and less familiar with pre 90's cars but if it has an IAC or TPS could be causing problems. Clean the throttle body/carb.

It might just need cleaning. Spray some PB Blaster around the throttle arm where the cable connects to at the base of the carb, and see if that frees up the flaps. And while spraying, fiddle with the throttle linkage.

If it idles that fast, the throttle isnt seated all the way down, either the linkage is stuck or the choke mechanism isnt letting the throttle close all the way. On a 2 barrel carb, if the secondary throttle isnt closed all the way it could also do that. Try cleaning the secondary throttle bore and make sure it operates smoothly and closes completely.

Clean the choke and linkage around the air cleaner again.

You are on the right track.

I will give ALL the intake manifold bolts a 1/6 turn....just to rule out leaky intake manifold gasket.

Check for loose or leaky vacuum hose.

Since you truck is 1987. I will replace all small vacuum hoses.

Change one at at time.

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Change the fuel filter
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Test fuel pressure
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Check the ohm specification on the coil.
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If the wires are over 3 years old then replace it
Check and clean contacts
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Make sure the wires are not cross.
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Do a good carb. cleaning and use Chevron gas for one tank full. Do some high RPM highway ran and see does it improve.

Have you tryed ajusting your carb choke?