Idle issue
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Idle issue Hello,
I've a Civic EP2 2004 hatchback 1.6 L manual transmission with 300k km. It starts great but after 1min the idle goes down to 500rpm, sometimes it stalls, then it goes up to 1800rpm. It repeats this until the engine is at operating temp. It stared that problem in winter and now is doing every day on cold engine - check engine on.
In neutral, the rpm goes up following my throttle but once released, it remains for a while at 1300 rpm, before going to normal 800rpm. Driving downhill in neutral, the rpm stays at 1500-1700 I have do to a full stop to have it at 800 rpm. I've cleaned the IACV and TB but I didn't replaced the IACV gasket since I'm not sure of the problem. Besides this, the car works fine once the engine is at operating temperature.
Many thanks in advance!
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I've a Civic EP2 2004 hatchback 1.6 L manual transmission with 300k km. It starts great but after 1min the idle goes down to 500rpm, sometimes it stalls, then it goes up to 1800rpm. It repeats this until the engine is at operating temp. It stared that problem in winter and now is doing every day on cold engine - check engine on.
In neutral, the rpm goes up following my throttle but once released, it remains for a while at 1300 rpm, before going to normal 800rpm. Driving downhill in neutral, the rpm stays at 1500-1700 I have do to a full stop to have it at 800 rpm. I've cleaned the IACV and TB but I didn't replaced the IACV gasket since I'm not sure of the problem. Besides this, the car works fine once the engine is at operating temperature.
Many thanks in advance!
Here's the link:
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Re: Idle issue
If it's not a sticking IACV as BC suggested then it might be a vacuum leak that seals when the engine gets to operating temp. Seal the throttle body and do a smoke test on it via the brake booster or other large vacuum line. There's info online how to make a homemade smoke tester or you can use a cigar and tubing as shown by Scotty Kilmer:
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