Bad Idle

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Dec 27, 2013 | 08:09 PM

MrPi

Thread Starter

Heel & Toe

Joined: Dec 2013

Posts: 21

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From: North Port Fl

Bad Idle

Hello I am very new here(just signed up) I have just recently bought my dad's '85 Corvette from him after my Jeep gave up the ghost.

I have noticed that the park and neutral idle is around 950 after it warms.

It seems like it wants to launch and almost dies while on the brake going from neutral to drive(automatic tranny).

It idles at 650 in drive and in park before the thermostat opens at 195F

I don't know exactly where to start to chase down this problem and looking for a 'cheaper' fix than taking it to a mechanic (poor college kid) plus I want to learn more about the car.

If anyone could point me in a direction it would be much appreciated. Thank You.

Dec 27, 2013 | 10:21 PM

Kevova

Le Mans Master

Joined: Sep 2013

Posts: 6,192

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From: near the thumb in the mitten

was car used regularly or just sat for long periods of time? if it just sat until needed it just may need driven. check air filter, for vacuum leaks, throttle body is not covered with carbon. Is or does check engine light come on?

Dec 28, 2013 | 12:44 AM

MrPi

Thread Starter

Heel & Toe

Joined: Dec 2013

Posts: 21

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From: North Port Fl

It was drove every 2 days at least and check engine light comes on every time I drive more than 20 miles Highway speeds 70ish unless I'm hard on it. Recently had transmission rebuilt (2 weeks) before I bought it

Dec 28, 2013 | 03:55 AM

Cliff Harris

Race Director

Joined: Apr 2002

Posts: 10,036

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From: Anaheim CA

Pull the error codes:

http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm

What they mean:

http://forums.corvetteforum.com/1576116036-post35.html

They changed over the years, so check the ones that apply to your car.

Dec 28, 2013 | 05:15 AM

pastamike

Instructor

Joined: May 2010

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Quote:

Originally Posted by Cliff Harris

saw this post before and on pulling codes,on my 1996 c4 i could not find an options button to press on, im i missing something or is info wrong for the 96.

Dec 28, 2013 | 06:45 PM

MrPi

Thread Starter

Heel & Toe

Joined: Dec 2013

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From: North Port Fl

I got code 43 electronic spark control. Would that cause the high idle?

Dec 29, 2013 | 02:19 AM

Cliff Harris

Race Director

Joined: Apr 2002

Posts: 10,036

Likes: 346

From: Anaheim CA

Quote:

Originally Posted by MrPi

I got code 43 electronic spark control. Would that cause the high idle?

No.

ESC is what they call the knock sensor and module. It retards the spark if it senses knocks.

Dec 29, 2013 | 11:27 AM

Red89'-L98

Burning Brakes

Joined: Mar 2012

Posts: 768

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From: California

FL Events Coordinator

St. Jude Donor'13

I would fix that code either way and also check your timing that is what cause my bad idle. I finally re-timed my car yesterday and it is driving and idling better than ever.