Weird/rough idle 2010 2SS

[Mechanicmike90]

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Drives: Chevy camaro
Join Date: Mar 2020
Location: VA
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Exclamation Weird/rough idle
I'm new to the forums here and a new camaro owner at that. But here's my issue. I have a 2010 SS 6 speed and I'm having some odd idle issues. Only mods on the car are CAI and borla catback. I do not have any check engine lights on or pending codes when scanned with a professional snap-on or similar scan tool. While running the live data stream you can see the misfire counter go up but again no specific code for a certain cylinder. I recently replaced the spark plugs with OE ACdelco from the dealer(no change). I run 93 octane whenever I fill up. I have checked and cleaned the throttle body already. I've picked the brains of all my master technician friends some with 20+ years in the field and we cant seem to find an issue. Any ideas on where else to look or things to try would be a great help.

Mike

[pnwdan]

The wires would be my next thing to check.

[canadian ss]

Sometimes an engine will count misfires that could be related to many things.

Just because you use 93 octane doesnt mean there isnt a slight contamination in it.

If there was an issue, it would set a P0300 code for multiple misfires detected down to a specific cylinder code.

If an engine was meant to run perfect in a perfect world, there would be no need for a knock sensor.

Dont sweat it. Scan another vehicle and watch the misfire counter on the roadtest. Even a blips of the throttle might show a slight misfire. Normal.

[Avenging Orange]

These cars out of the factory have idle fluctuation. It does have a slight cam in it. Many mistake this for an issue. If you are able to post a video...might be able to help a bit more.

[Mechanicmike90]

Originally Posted by Avenging Orange

These cars out of the factory have idle fluctuation. It does have a slight cam in it. Many mistake this for an issue. If you are able to post a video...might be able to help a bit more.

Yeah soon as the weather clears up I'll post a video.

[Ammo_Don]

Originally Posted by canadian ss

Sometimes an engine will count misfires that could be related to many things.

Dont sweat it. Scan another vehicle and watch the misfire counter on the roadtest. Even a blips of the throttle might show a slight misfire. Normal.

Wait what? I have misfires in mode6 data. I datalogged and they ONLY happen when the pedal is barely pressed like coming from a coast to light power, or when I blip to downshift. These are normal? Mode6 reads like 20-30 each hour of driving in all cylinders.

At idle and cruising at 75 on interstate I get 0 misfires.

[canadian ss]

Originally Posted by Ammo_Don

Wait what? I have misfires in mode6 data. I datalogged and they ONLY happen when the pedal is barely pressed like coming from a coast to light power, or when I blip to downshift. These are normal? Mode6 reads like 20-30 each hour of driving in all cylinders.

At idle and cruising at 75 on interstate I get 0 misfires.

Blipping the throttle to down shift and applying acceleration from a coast could cause minor and insignificant misfires. The counter will count and like you said 20-30 in an hour??????? Normal.

During idle and cruising you see 0 misfires. That tells me there is nothing wrong with your engine. If there was, it would count constantly. You have to allow error for incomplete combustion, quality of fuel, performance upgrades that hamper a tune, carbon build up, blow by, air quality, dirty injectors etc.

When we see a CONSTANT misfire count or large misfire numbers in many cylinders due to shorting ignition or bad injectors, then its a concern.

Obvious engine damage causing a misfire like a worn cam, etc. will also count huge misfire counts.

To have a slight count like you mention(20-30 an hour) is no need for concern especially if you have no SES light on. New era sensors are very sensitive and will count the slightest stumble.

[Ammo_Don]

Originally Posted by canadian ss

Blipping the throttle to down shift and applying acceleration from a coast could cause minor and insignificant misfires. The counter will count and like you said 20-30 in an hour??????? Normal.

During idle and cruising you see 0 misfires. That tells me there is nothing wrong with your engine. If there was, it would count constantly. You have to allow error for incomplete combustion, quality of fuel, performance upgrades that hamper a tune, carbon build up, blow by, air quality, dirty injectors etc.

When we see a CONSTANT misfire count or large misfire numbers in many cylinders due to shorting ignition or bad injectors, then its a concern.

Obvious engine damage causing a misfire like a worn cam, etc. will also count huge misfire counts.

To have a slight count like you mention(20-30 an hour) is no need for concern especially if you have no SES light on. New era sensors are very sensitive and will count the slightest stumble.

I was told today by a few people that it is the DFCO, basically that when coasting the fuel is cut off and when u apply throttle whichever cylinder is firing doesn't have gas to burn so it reads "misfire." I was told not to worry about it so I just don't look anymore. Lol.

[Bigdumogre]

Might be normal like stated or maybe change the wires next. Mine were the original from 2012 and when I changed them this year 2 of them were dry rotted and broke apart.
Also perform a fuse pull