2.0L LSJ Performance Tech 205hp Supercharged SS tuner version. 200 lb-ft of torque.

Idle problem CURE!!!!!!!! Finally!!

Old 03-13-2019, 07:45 PM
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Originally Posted by Angel View Post
Ok, I have been one of the thousands of victims of the horendous idle problem with my 07' Cobalt SS Supercharged. I do have many mods including the Stage 2 upgrade along with the K+N Typhoon Cold Air intake system and exhaust and many more. I noticed shortly after installing the Stage 2 kit that my cars idle was bouncing at idle and the problem got worse and worse to the point whereas I was stalling in traffic. I was forced to basically ride my clutch like nobodys business and it was just plain annoying. Pulling up to a red light and people looking at me thinking I was a young 16 year old wanting to show my ride up cause my rpm was consistentally bouncing from 400-1400. My fuel mileage has progressively gotten worse and it had started to become a safety issue considering I was almost t-boned as I rolled through a downhill stop sign trying to beat traffic but my car stalled again!!!

Anyhow, I am aware that there are many other balt owners out there who are experiencing the same problem as myself and I have seen what others were trying to do to fix this god aweful problem with no prevail. I have been working with the head GM tech in my city here for a while now to see if we could finally put this issue to rest. After months and months of monkeying around and ruling almost everything out except for a possible computer error in the car that wasnt tripping any codes which would be unlikely I thought to remove my throttle body to have a look. Just for the record all of you cobalt owners this is soo simply a blind monkey can remove the throttle body. Simply remove your intake and the throttle body is attached with 4-10mm bolts and 1-Vacuum line and 1-Electrical connector. Once removed I noticed that I had a bit of gunk in the body(not a significant amount and keep in mind my car have only 5k miles on it) but I figured I would give it a good cleaning with a $5 spray can of throttle body cleaner and then clean right around the valve(keep in mind when you open the valve be very gentle when cleaning to avoid any unwanted strain or possible damage). Once this minor operation was finished I reinstalled everything back to normal and fired it up and HOT DAMN!!!! Back to normal baby! Everything is running 100%. No more funky butterfly idle problems and my gas mileage is back to normal.

I cant believe I didnt figure this out long ago but s**t happens I guess. Anyhow, I know many of you are going to be wanting to jump all over this and fix your own problem but read this before you do. I dont like just fixing problems and saying "great its done" I want to know what caused this considering the car is so new with so few miles on it??? Im not 100% sure but I would assume it has alot to do with the filter being mounted so close to the ground and possibly some oil from the K+N filter and mabye some other debris happen to make its way up which would be strang but no impossible. My only possible solution to this rather than doing this cleaning every 5k miles would be for all of us to install oil catch tanks to allow some of this crud to remove itself from the intake and then every once in a while remove the vacuum line on your intake while the car is running and give the hole in the intake a quick spray of the throttle body cleaner.

Ohh and for you wanting to know why this problem was doing what it was doing is simply this - when there is any type of crud or oily compound around your intake valve and the valve may possibly stick a bit the vehicle recognized this and sees that it is sticking so it rushes to correct and overcorrects causing the valve to be opened to much and drops quickly causing the fluctuation from anywhere from a couple hundred rpm to 1500 rpm or so. I hope to god that this helps hundreds if not thousands of other owners out there who have been experiencing this problem because it drives us CRAZY!!! and I was near ready to go buy a gallon of gas and a match if a solution didnt come along right soon. Anyhow, please post replies once this is tried and let me know. I am very very curious as to how many people this is going to help.
Not sure what the verdict was; specific to supercharged engine/ manual or auto. Doesn't matter, check your throttle body now if your reading this!

I read this whole thread OMG, wish I read this a long time ago...
Been getting some weird idling, misfiring & vibration issues when holding a steady rpm.
Lately things have been getting progressively worse:

Starting a car in the morning, air fuel will be low, and it will climb to 14.69(if your N/A), wheel its been taking longer and longer, and its heating up outside not getting colder.
Been getting more misfires when coming to a stop, misfires leaving a stop. These are not peg leg misfires, its a one single falter you could very easily miss if you didn't have a gauge to watch.
But stranger things have been happening, I had the other day 16 misfires after starting my car which was really a oh **** moment.
the Other day, started the car and it stayed at about 12:1 air fuel, I had to depress the accelerator and hold till it got to 14.69.
Twice now, coming to a light for a stop, air fuel rose to 16:1 for a split second. That should not happen.

Probably the most concerning was the vibrations when holding a slight acceleration. I could smash throw gears and be fine, but holding a 100km/h or slight acceleration above 60km/h I would get a bellowing/ grinding/ shudder noise.
My first thought was great, torque converters is going, but a friend helped me kick that idea out quick!
I have yet to measure a misfire when this is occurring, air fuel is fine, wheel bearings inspected, tires are fine.
Injectors, Spark plugs, Fuel filter, everything is new and checks out. Trans was inspected, re filled, etc

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Old 03-13-2019, 07:56 PM
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I wanna say thankyou Angle, It takes 30 seconds to check a TB, maybe two minutes to remove it.
The first thing my friend suggested to me was TBS, I was like no way bud. No Codes= Not sensors, its mechanical.

My TB was black,
Worse yet, My Intake Manifold..... FILLED WITH OIL.
So yeah, wanna hug you Angle, Im not out of the water yet, but willing to bet,
We have found our Problem

Bump a million ******* times for the next guy
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Old 03-13-2019, 08:06 PM
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Old 05-20-2019, 12:36 AM
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I cleaned it and it helped BUT!!!!!!

It helped but it still does the same thing not as bad but does it and i feel like it takes for ever for the coolant to get where the car needs it to run if not I feel like the car doesn’t get air from exhaust and bubbles up and go’s. Someone help got check engine light on got told bank 1 sensor 1 is bad and mass air flow sensor
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