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5.3l idle issues.

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Old Dec 24, 2013 | 08:52 PM
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I Confederate I's Avatar
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Default 5.3l idle issues.

Ok I have a vortex 5300 in my 04 Tahoe. All stock. I thought I would ask here first, considering it is an Ls/lq base platform. When it's at idle its running extremely rough. Headlights are dimming and it feels like a misfire. I treated it like a misfire, did plugs, filters, cleaned TB, checked for vacuum leaks, all general maintenance stuff. That didn't fix it. I dug a little deeper, pulled the intake manifold, checked for cracks, pinched/bad gasket, nothing. It isn't throwing any codes, so the computer isn't picking up whatever it is. It should be noted that we just replaced the heads with 706's. The old ones were cracked. It was done by myself and a good friend who is a former GM master tech, and this issue started shortly after. Myself, as well as my friend, cannot seem to find the problem. I don't want to go to a shop and have them shotgun parts at it hoping it will fix it. Any help is greatly appreciated.
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Old Dec 27, 2013 | 08:22 PM
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cold_surfer's Avatar
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missing ground wire ?

did you clean inside the IAC ? pull each plug and check their condition. white? Tan ? red ? black ? brown ?

1 can of deep-clean lucas fuel inj cleaner
+ 16 oz of lucas fuel additive (honey type stuff)
+ 1 tank of midgrade gas
= miracle clean system
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Old Dec 28, 2013 | 10:12 PM
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I looked and searched parts houses, I can't find an IAC valve on the 04's, as in, they didn't have one. I'll try running that mix though.
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Old Dec 28, 2013 | 10:24 PM
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Well, you partially answered it with stating that your problems started after the head swap. You need to backtrack. I agree with the post above about the ground wire(s) on the back of the head.

Were the heads refreshed? Hopefully it is sucking coolant or something on start up (warped heads).
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Old Dec 28, 2013 | 11:50 PM
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Originally Posted by lt1pwr1
Well, you partially answered it with stating that your problems started after the head swap. You need to backtrack. I agree with the post above about the ground wire(s) on the back of the head.

Were the heads refreshed? Hopefully it is sucking coolant or something on start up (warped heads).
They were brand new heads. Agree though. Hopefully it isn't a bad set.
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Old Dec 28, 2013 | 11:55 PM
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Just checked the strap. Its tight.
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