Ruff Idle

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Sep 13, 2023 | 02:54 PM

C7Help

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Ruff Idle

I have a 2007 Z06 that is cammed and tuned, owned the car about 10 years. Driving it one day it got a miss, I have changed the plugs, cleaned injectors, ran Techron adder, cleaned mass air and throttle body. Hooked it up to a computer and no codes or light, O2 senor was a little sluggish. Installed both O2 sensors and still there. I can start the car, and everything sounds great till you tap the throttle the engine revs up and back down once it comes down it has a ruff idle like a miss. After a few seconds it will smooth out and sounds fine till you tap the throttle again. The car was built and tuned when I bought it, not sure who tuned or what tune is in it and the stamps on the head look like factory heads. Car has 23K on odometer. Any information is greatly appriciated, I don't want to throw money at it.

Sep 13, 2023 | 03:57 PM

Blizzard1975

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From: Helsinki, Finland

Check for vacuum leaks. E.g. are intake manifold bolts properly tightened.

Sep 13, 2023 | 05:12 PM

C7Help

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Quote:

Originally Posted by Blizzard1975

Check for vacuum leaks. E.g. are intake manifold bolts properly tightened.

I will double check and get back with you.

Sep 14, 2023 | 08:13 AM

C7Help

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Bolts are properly tightened on the intake.

Sep 14, 2023 | 08:46 AM

C5 Diag

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From: Cape Coral, Florida

It looks like you have a scan tool so why don’t you hook it up and see what your MAF, fuel trims, and O2 sensors are doing…upstream O2’s should be “oscillating” between 200-800 mv’s.

Sep 14, 2023 | 11:02 AM

C7Help

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O2 are 400 to 600 at idle, what should the rest look like?

Sep 14, 2023 | 12:55 PM

C5 Diag

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From: Cape Coral, Florida

When you replaced the O2 sensors are they OEM ??…what brand ??…do you mean they are still sluggish after changing ??…MAF (in not speed density tuned) should read the liter displacement of the engine at “hot unloaded” idle…ie…no electrical loads…downstream O2’s should be steady (not oscillating) at about 700-800 mv’s…video below…fuel trims should not be more than plus or minus 10%…with ignition in RUN and engine OFF and scan tool connected the O2’s should read 450mv’s…the bias voltage.