1986 f150 plenum gasket

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Dec 21, 2003 | 04:46 PM

liljase

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1986 f150 plenum gasket

I was wondering if anyone knows how to tell if a plenum gasket is bad.I think I have a vacuum leak but can't put my finger on it.The truck has a 302 and is fuel injected.When you are in drive and the rpms are low the idle fluctuates a few houndred rpms.Any info would be greatly appreciated.

Dec 21, 2003 | 05:07 PM

Franklin2

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If you take the throttle body and IAC valve off and clean both, and still have the problem, the plenum gaskets would be a good place to look.

Dec 21, 2003 | 05:25 PM

liljase

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Thanks for the reply,I just took off the throttle body and cleaned it out and laso replaced the IAC and TPS.How long does it take to do the plenum gasket and what else should I replace or look at while doing it?Thanks again

Dec 21, 2003 | 05:33 PM

Franklin2

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From: Virginia

Never have done that job, but there have been a lot of posts on here where those gaskets have fixed some strange problems. It won't be money wasted.

Dec 21, 2003 | 09:12 PM

Txquadhunter24

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It only takes about 30mins to hour depending how fast you work and what else you do. Another thing If you have a Leaky Pass. side valve cover now is the Time to change it since the plenum has to be removed to get to it.

Hope this helps

Dec 21, 2003 | 10:12 PM

liljase

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Thanks for the help guys.I'll replace the valve cover gaskets as preventive maintenance.Any idea what the effects of not having a smog pump belt hooked up would be.The previous owner said it was making a poping noise so he removed the belt.I dont know if that would have any negative effects on performance.If so I will replace the pump.Thanks again