high rev when driving

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Dec 7, 2005 | 11:07 AM

estrenge

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high rev when driving

I did a quick search and didn't find an answer.

My '81 f250 351 automatic revs high when is starts as usual and then idles down when I tap on the gas. When I'm driving around town it will run at a high rpm and won't come done much if I tap on the gas again.

Any ideas?

thanks, Eric

Last edited by estrenge; Dec 7, 2005 at 11:18 AM.

Dec 7, 2005 | 02:37 PM

Kemicalburns

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From: Bend,OR

rebuild your carb and check for vacum leaks

Dec 8, 2005 | 10:51 AM

estrenge

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Wouldn't a vacuum leak do the opposite and cause the rpms to drop and kill the engine?

What specifically in the carb would need to be fixed/adjusted?

Dec 8, 2005 | 12:24 PM

Kemicalburns

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From: Bend,OR

vacum leaks allow more air in and in which cause will lean out the motor and make it run at a higher idle. to much of course could cause it to die to.
the rebuild kits are cheap and have everything you may need like powervalve,gaskets and a new float. also clean it real good with carb cleaner its possible the butterflys are sticking open to

Dec 8, 2005 | 01:02 PM

fearfactory

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From: Central,IL

Yea a vaccum leak will cause high idle.I had a vacuum leak on my truck a few years back and it idled at 2k

Dec 13, 2005 | 09:40 AM

estrenge

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Is there an easy way to check for vacuum leaks, or do I have to replace all the hoses?

Dec 13, 2005 | 09:59 AM

Kemicalburns

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From: Bend,OR

if you spray the lines with quickstart the idle will increase and you can locate the leak. if your motor has the hard vac lines figure to just start replacing them because they get brittle and dont last. regular rubber vac lines will work just fine. replace one at a time though so they get hooked up correctly. its not so bad once you get started honest