Stumbling/rough idle
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Joined: Dec 2004
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From: Bloomington IL.
Stumbling/rough idle
I have an 86. After a hard excelleration, it started running rough. Erratic idle. If you stab the throttle hard, it revs, close to normal. If you ease on the throttle, it stumbles and does not increase RPM. Any thoughts? It does have a bigger cam, headers, head work, etc. Have not had an issue in 10 years of ownership.
Last edited by boceltics17; May 17, 2015 at 03:38 PM. Reason: Additional information
Race Director
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I have an 86. After a hard excelleration, it started running rough. Erratic idle. If you stab the throttle hard, it revs, close to normal. If you ease on the throttle, it stumbles and does not increase RPM. Any thoughts? It does have a bigger cam, headers, head work, etc. Have not had an issue in 10 years of ownership.
Le Mans Master
Joined: Aug 2007
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From: WV
run a fuel pressure test - might as well establish a baseline. I'd say the next thing to do is pull the throttle body and give it a good thorough cleaning including the IAC valve. pay attention to all the small "idle" passages within the TB. if you have any doubts about the IAC, give some thought to replacement. double check the pintle dimension - should be about 28mm. check the voltage values for the throttle position sensor, and double check for any vacuum leaks. good luck - keep us posted.
...WW
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From: Bloomington IL.
I will take those suggestions. It appears to be somewhat of an intermittent problem. After checking a few random things, i have taken some test drives. Engine already warm, I will leave at it is running fine. Then it starts acting up. Mid range throttle, easy into the throttle it seems like it is missing, popping. Given it full throttle and it excellerates.
Le Mans Master
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From: WV
...WW.
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Last edited by WW7; May 18, 2015 at 10:53 AM.
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Thread Starter
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Joined: Dec 2004
Posts: 62
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From: Bloomington IL.