miss at idle

1995 GMC SIERRA
132,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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JODA
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Hi, my truck has a bad miss at idle runs good at higher speeds. I replaced the EGR and the distributor and coil with new ones. I also have installed a throttle body spacer by hyper tech .also replaced the master brake booster and fluid container .
thank you any help will be greatly appreciated.
Joe
Oct 26, 2019 at 12:14 PM
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KASEKENNY
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Hi,

When did this misfire start? Was it after the throttle body spacer? Also, what is the truck idling at? If you added a spacer, you may need to reset your IAC.

Lastly do you have a check engine light? How do you know this is a misfire and not a vacuum leak/rough idle? Do we know which cylinder is misfiring?

Here is a guide that goes over misfires at idle. Attached is a bunch of info about IAC and testing for rough or unstable idle.

https://www.2carpros.com/articles/engine-vibration-at-idle

Let me know what you find and we can go from there. Thanks
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Oct 27, 2019 at 3:55 PM