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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: the_legend_1981 on March 12, 2009, 05:56:13 pm

Title: high idle
Post by: the_legend_1981 on March 12, 2009, 05:56:13 pm

When i come to stops my truck idles real high. Sometimes I can get the idle to kick down, but other times i can't. Then when i go to shut it off it will diesel if its idling high. I turned the idle down...not sure if it could be the throttle cable, choke or what. Thanks for any input.

Title: Re: high idle
Post by: the_legend_1981 on March 12, 2009, 06:55:22 pm

its the actual throttle on the carb thats sticking i just went and checked it. i could set it back in place with my hand. how can i go about fixing that?

Title: Re: high idle
Post by: oldwhity on March 12, 2009, 07:00:28 pm

Mine used to do that all the time. I sprayed the linkages down with some carb cleaner and it stopped. I would try that before trying to readjust any linkages.

Title: Re: high idle
Post by: the_legend_1981 on March 12, 2009, 07:03:11 pm

Would it be better to use lubricant?

Title: Re: high idle
Post by: 78 Chevyrado on March 12, 2009, 09:34:33 pm

no , only use carb cleaner, it will lube it and using oil will catch a lot of dirt being out in the open and gum it up sooner.  spray carb cleaner in it while working the linkage and it will do the job.  if you have cruise control, make sure it's not binding, I had one cause that same problem one time.

Title: Re: high idle
Post by: Stewart G Griffin on March 23, 2009, 12:56:07 pm

The other thing i want you to check is the throttle spring itself.  Can you post a picture?  What may have happened is that the spring has lost tension and overstretched.  This happened to me last yr. and i was getting the same symptoms.

Title: Re: high idle
Post by: the_legend_1981 on March 23, 2009, 01:12:44 pm

I did sll that stuff even changed the throttle spring...then I finally figured it out as I was doing that. The carb was just a little bit loose, I tightened it and it hasnt stuck so far.

Title: Re: high idle
Post by: Lt.Del on March 23, 2009, 04:04:51 pm

now that would make for quite a vacuum leak, which is basically what it is and kept the idle high.  Too much air.

Title: Re: high idle
Post by: the_legend_1981 on March 23, 2009, 04:10:19 pm

yeah it was the last thing i expected it to be.

Title: Re: high idle
Post by: Stewart G Griffin on March 25, 2009, 12:20:13 pm

OK, cool.

Title: Re: high idle
Post by: VileZambonie on March 25, 2009, 07:07:13 pm

Is this a quadrajet? If so you're probably not kicking off of the fast idle cam all the way. Check the choke break.