06 Cobalt Rough Idle/Stall when stopping or quick deceleration


Asked by dragon300zx Dec 16, 2009 at 10:20 AM about the 2006 Chevrolet Cobalt LT

Question type: Maintenance & Repair

Hello All,

Here is the problem I have.

06 Cobalt LT 2.2l 103065 Miles

When decelerating on the freeway to come to a virtual stop for traffic, when stopping at a stop light, when pulling out of the driveway, or at any point when the RPM's fall quickly to idle speed I have an irratic idle.

Idle will fluctuate between 300-750 rpms

Normal idle is around 750 rpms

This morning it actually stalled when I was pulling up to a stop sign to pull out of my subdivision. It did restart right away.

When the Idle is rought the lights dim on the car, power steering becomes weak, and other problems you would expect when your idle drops and your car is about to stall.

No check engine lights come on at all (I wish they did, I have a nice scantool).

If I decelerate slowly, or have been driving at even driving conditions (not alot of accelerating then decelerating) this doesn't really happen.

Any ideas? Has anyone had this happen?

I just bought this car alittle over a month ago and rely on it so I need to figure this out and get it fixed.

30 Answers

Tom Le

well if the lights dim check the battery and charging system. with out a power source system start to fail. next i would check vacuum leak

8 out of 8 people think this is helpful.

I have the exact same problem with the exact same car! Did you ever find any solution to the problem?

29 out of 29 people think this is helpful.

Hello. I have a 2006 Cobalt LS with the 2.2 doing the same thing. Have you found the problem yet?

18 out of 18 people think this is helpful.

Hey guys, K well i hope this helps you out. I decided id do a tune up and replaced the spark plugs, oil change, and i sprayed out the throttle body with carb cleaner which had alot of build up in it. Like i said i had the exact same problem of my car nearly stalling everytime i braked and all the lights dimming. As soon as i did the tune up. The car is running like it was new again and isn't doing any of the above problems it was before. So if you haven't tried this yet i recommned it. It fixed my problems. Anyways good luck!

10 out of 10 people think this is helpful.

Mine is a 05 and does the same things. We've replaced the fuel filter, spark plugs, cleaned throttle bodies, and replaced the whole gas peddle and electrical unit with it, It got better for a couple days but has started up again. Any ideas?!

11 out of 11 people think this is helpful.

Had 100% same problem - just fixed it yesterday. Hope it will help to others: all my mechanic did is cleaned the air intake system, and injector, after that the car runs like new - the rpm hold steady, a little below 1000, no drops or anything. All of the problem caused because car doesn't have enough oxygen flowing in.

14 out of 14 people think this is helpful.
You think this is helpful.

I have the same problem with my 2006 cobalt.Today i decided to take the whole intake a part and cleaned inside and the T.B.I.(was a lot a oil deposit on it) After that change the fuel filter,spark plug and done problem solve.I noticed the bolt on the intake was not enough torque on it.I replaced all the rubber gaskets too.If you have a problem where the car dont rev over 3,000 rpm you got problems with the MAF Sensor (Mass Air Flow )Its gone to show in the dash Power Reduced.Hope this helps!!I

7 out of 7 people think this is helpful.
You think this is helpful.

I have the same car with same problem. It took the throttle body off and cleaned every inch of it, and used a q-tip in the vacuum hose also. On fuel injected engines this is called a "tune-up" your mechanic should have tried this first. There is a ton of carbon build-up in these intake's. only requires removing 4 bolts from the body and the air intake off of the top, and a $2 can of cleaner. Idle runs strong now,with no hesitation. of course i have 50 electrical issues to figure out, buying a ford next time around.

12 out of 12 people think this is helpful.

I have had the same problem on my 05 Cobalt. After delaying the maintenance on it because I have been so busy at work. I finally decided to investigate this problem. It is a simple fix. The throttle body intake valve is not closing all the way. Buy a can of throttle body cleaner. All you need to do is take your air intake box off to acess your throttle body. you will probably notice that where the valve is inside has became very dirty. Spray some of the cleaner ON A RAG and wipe off the valve and the walls around it. you will also need to manually open the valve and clean down beside it. It takes about 10 minutes to complete this. Re-assemble and test drive. The car should drive like a brand new one.

10 out of 10 people think this is helpful.

Hi, I have a 2006 Chevy cobalt 2.2, I was having the same problem with the car stalling or wanting to at first, it was worst in the colder weather. in the summer the ac was not even working right. But I cleaned the Throttle Body. I pulled it out spent like 4 bucks on a can of throttle body cleaner and sprayed it good. The car runs great.

8 out of 8 people think this is helpful.
Jonathan Wakefield

Same problem here, with a 2005 2.2L. My car was showing codes for both O2 sensors, and MAP sensor. It has 127k miles. I did a tune-up at 100k miles. (spark plugs, k&n filter, belt, and went to full synthetic oil) I noticed the car having a rough idle when slowing down. I recently bought a bottle of seafoam, and did an oil change and cleaned the k&n. After 1000miles my car has significantly inproved. Im going to clean my throttle body next, hopefully it fixed the problem further. I now have no error codes showing.

2 out of 2 people think this is helpful.

Anybody currently having this kind of problem here is what I did to solve it. I took the air cleaner off. The inside of the throttle body air intake was black sludge. Using a fuel additive, I wiped out what I could and then poured some into the throat until it was pretty clean. Berrymans B12 spray would have been better and the stuff works great. I just did not have any. DO NOT spray it or any other carb or brake cleaner on anything else. The stuff will damage plastics, rubber and paint. . Do not move the butterfly valve inside the throat. Replace the air cleaner carefully making sure the rubber gasket fits all the way around the throttle body properly and then tighten the screw firmly. That solved my problem. If by chance you get an engine warning light, disconnect the car battery for a few minutes and then reconnect. That resets the onboard computer. You should have no further problems. Automobiles today are really sensitive to air intake. It seems to affect everything including how your transmission shifts. This is a simple task. Don't rush it. A screw driver and a pair of pliers are all you need.

5 out of 5 people think this is helpful.

and just to add...Please stop repeating comments...everybody knows cleaning the Throttle body helps if its dirty but that doesn't solve the problem completely for a whole lot more people. The problem with GM TB in the newer balts is this...It does way too many functions as one device. in theory its great. You have the Throttle control and the Idle air control and its all automated AND it electronically controls down-shifting int he transmission. great fantastic. except the electronics are completely unreliable...so its just a disaster.

2 out of 2 people think this is helpful.

vizard answered 21 minutes ago FIXED...semi-fixed anyway. Ok so here's a complete step by step process on how to fix your idle stumble issues. Step one: clean throttle body with brush and carb cleaner. NO HARD OR METALIC BRISTLES only plastic or else just wet a clean rag and wipe. step too remove all hoses connections and everything from plastic intake manifold. step 3: please clean every single grove of the mating surfaces that are supposed to have a green "viton" gasket on it. they should be reusable especially if the car is under 100K. if its more than 100K change them anyway regardless of how they look. please be careful to minimize and reduce any sand or dirt getting into the manifold during and after removal. to help facilitate this safety try to blow how the dust with compressed air or with a "duster" can you can get that at an office dept or just about anywhere really. Step 4: use a plastic bristle brush and clean all gasket grooves with carb cleaner and a PLASTIC bristle brush. use a toothbrush. you're supposed to get a new one everymonth anyway. Install reverse of removal and please please make sure you torque the bolts on the engine head to the RIGHT specifications. Do not over torque. Remove the fuel rail and injectors if you already haven't done so. please used compressed air to clean area before doing this. replace ALL GASKETS AS A SET the gaskets are O-RINGS. you can replace all the lower ones if that's easier and please replace the one on the plastic grey cup at the end of the injectors. If injectors are dirty pleaes clean with carb cleaner and a plastic toothbrush. the spray alone will not clean it all. install is reverse of removal. please torque the retaining bolts (2 holding bolts) to the CORRECT TORQUE. overtightening and undertightening have concequences. so be reasonable if you don't ahve a torque wrench. Step five: use seafoam upper engine treatment OR b-12 chemtool. They are both very good. You can google how to do this on the car as it may take too many words. Place 1/2 or follow instructions on how much should go in gasoline. if you have any problems figuring steps out then by the haynes repair manual. it helps. After this you have to "relearn" the idle speed and throttle position. they are findable in google and they are in the repair manual. 0 vizard answered 10 minutes ago relearning idle position and idle speed step by step process: Step 1: turn ign: to ON position and do not start. IMMIEDIATELy pump the accelerator ALL THE WAY DOWN and ALL THE WAY UP quickly and smoothly SEVEN times in under Five Seconds. repeat this like 3 or more times to make sur eyou do it right. AFTER you do the last set do not turn the IGN key off but wait 2 seconds after the initial five seconds and then crank. any check engine light should go away and PCM should be reset. Step 2: Let the car warm up to normal operating temperature. Setp 3: drive the car around moderately and idle with only slight acceleration to moderate acceleration if needed. OR you can drive around moderately until normal performance returns. Step 4: place the PARKING BRAKE ON and LEAVE the SHIFTER in DRIVE for automatics and "NEUTRAL for all MANUALS. Step 5: let the car idle in DRIVE for autos and NEUTRAL for manuals/stick shift for a total of 2 minutes. turn off the car.. idle should be relearned now. everything should be working normal now unless there is some vacuum leaks, OR spark plugs faulty or incorrectly gapped, or APP(acell pedel position sensor) or something else is not working like it should.

5 out of 5 people think this is helpful.
Melvin Richardson

i just left my mechanics for this exact same problem car kept stalling at red lights or stop signs or quick decelaration. after reading online about other like causes he took off my air intake box and the throttle body off ,throttle body had dried black sludge on the butterfly and on the throttle body walls ,he cleaned them both . so far so good it even seems like there is more power no stalling yet.

2 out of 2 people think this is helpful.

Is there anything else that can be done to fix this? We replaced the throttle body, air filter and throttle positioning sensor and it's still doing the same thing...I've been dealing with this for well over a month. I hate this car! Any other ideas that would work?

3 out of 3 people think this is helpful.
Dwayne Smith

I think it is a much simpler fix, i cant remember the name of the part, but the oreilleys part number is CP561. $20 and five minute swap. Havent tried it, dont have the time. Someone who is a do it yourself type person should try and report back. I know it isnt a dirty maf sensor, air filter, or electrical problem, done all of those multiple times with no luck.

2 out of 2 people think this is helpful.
Dwayne Smith

Canister purge solenoid cp561 bwd

2 out of 2 people think this is helpful.

That's if it isn't working or stuck open. I tested it and that was NOT the problem. it was leaking air at the orings of the intake manifold and the fuel rail

1 out of 1 people think this is helpful.

oh sorry not to mention this earlier but if you suspect air leaking at the fuel rail and intake manifold. buy a can of brake parts cleaner or good carb cleaner and spray around the fuel rail and intake manifold. if the idle changes you have an air leak then refer to my long instructions on how to fix it. THOSE LONG INSTRUCTION WILL FIX IT IF YOU DO ALL OF THEM.

2 out of 2 people think this is helpful.
Rhonda Dempsey

I have 2007 and its the Purge solenoid sensor and throttle body sensor. I haven't replaced it yet bc its around $400! I may try cleaning it before I.dish out this money

1 out of 1 people think this is helpful.

Hi everyone! For those who haven't had luck resolving this issue... Here's what it took to fix my 06 with 107k... Started as a rough idle, nothing horrible but very irritating. Progressed to horrible idle, random stalling, RPMs all over the place & no acceleration power. Had it towed to Monro car center & they told me it was the fuel filter (?!). I let them replace the filter & I was on my way. Problem returned 10 miles later when I shifted into reverse. Then I read these comments & I did the throttle clean. This solved my problem for about 100 miles. Finally I consulted a mechanic & he ran a diagnostic. Turned out I had a code in my system for a random multiple misfire (pending code with no engine light). Since I had a tune up at 100k we deducted that the ignition coil pack needed replaced. It's a 10 minute fix... DON'T let a shop do it, they will rape you!!! I did it myself & my car now runs like a dream! :)

4 out of 4 people think this is helpful.
Greg Dilger

We have a 2006 cobalt 2.2L with same issues only we have a check engine light on with it. The diagnostics pointed to the MAF sensor so we replaced it 1st. There are no vacuum leaks and the light is still on and still idling issues. I do believe taking the throttle body and idle air control valve off for a good cleaning will fix this issue. Dont forget if you have a check engine light on to disconnect the battery for a few minutes to clear the code. I will reply once I have finished this and let you know the results.

1 out of 1 people think this is helpful.

1/7/2014 i bought a new air filter and mass air flow (MAF) cleaner. i also bought injector cleaner, which i did not use yet in the fuel tank. the process i used was, i replaced the the air filter with a new one and cleand the mass air flow sensor, located in the black air filter housing. then i took off the plastic coverings, sprayed the throttle body inside with the mass air flow cleaner and wiped it out with a rag without removing the throttle body from the engine. it seemed to work bc i dont lose rpm's. i barely noticed the interior lights dim at all. i guess i will find out if i fixed the problem when i drive it more at stop and goes. advanced auto said if that doesn't work, try the fuel injector cleaner and maybe replace the fuel filter. it seemed to drive alright just cleaning the throttle body and MAF sensor and replacing the air filter

1 out of 1 people think this is helpful.

I am driving a toyota vits (2000 model) import. after driving 1000km on a road trip I was on a stop sign and the and the engine just vibrated 3 - 4 times and it stalled. i switched it back on and i was able to make my way. following morning it startd perfectly, but as i was decelerating to a stop sign in vibrated again and stalled. after stalling a few more times, it run okay the rest of the day (no vibrating or stalling). I should mention that it recently got a new head. when its not stalling on stop signs or vibrating when decelerating engine sounds fine. I am looking at replacing the throttle, mass air flow sensorair/fuel filter. I also noticed that the engine is taking forever to warm up. Could it be the thermostat as well. PLEASE HELP i have spent enough on this car and i a looking for a somewhat lasting solution


I found website that explained got their answer I copy and paste what the person say... turned out to be a bad coil on cylinder # 1. Replaced coil and she runs great now. Thx for input.

2 out of 2 people think this is helpful.

After many hours verifying ignition and fuel ok, we ran the scan tool live , and discovered irratic readings from the MAP (Intake Manifold Absolute Pressure) sensor. Replacing the sensor was the solution. On a Cobalt, the sensor is under the throttle body.


I had replaced MAP it do not help also i clean Thottle body same thing only after when engine hot it drop RPM.


Look at the brown wire connection. It is located in the large square plug connector beside the throttle body. There are Hither six or eight wires in and out of the plug. Mine was poorly crimped and had broken. after it was repaired all the crazy problems disappeared

Holly Armijo

I have a 2006 cobalt 2.2 lt eng.. automatic. .I've had it for over a yr and It has been hormonal since day one.. at first it started out stalling and idle was off.. now its progressed into taking fifteen mins to start it after dying, bogging out and chugging harshly.. with it going haywire with alerts like service airbag, engine power reduced, theft, oil life reset tc light and not to mention my alarm goes off everytime I get into it... once in a great while it starts with no prob but its very rare! I'm a single mom and can't afford mech. Pls help

Your Answer

Add photo

Related Questions

  • Why no airbag deployment? 6 answers

    Car is still under warranty. Two accidents. Both front end. No airbag deployment. Why, I was told by a Chevrolet Dealer, that I had not hit the deer in the right place. What does that mean. Was the ...

    2009 Chevrolet Cobalt LS Coupe


    Maintenance & Repair

  • Transmission 'Jumps' from first to second gear 4 answers

    2004 Chevrolet Classic (Malibu) with 208K miles. Starts and runs great. When Accelerating, there is a very physical 'Jump/Bang" going from 1st to 2nd gear. Does not do it when decelerating.

    2004 Chevrolet Classic 4 Dr STD Sedan


    Maintenance & Repair

  • sudden acceleration/ sticky accelerator 3 answers

    i was just in an accident with my 2004 optra. i was driving on a stone road and when i put on the accelerator a little bit it floored it and when i slammed on the brakes it would not stop because the ...

    2004 Chevrolet Optra


    Maintenance & Repair

  • why wont my 4.3 rev past 3000 rpm 9 answers

    my 4.3 idles good but wont rev over 3000 rpm. it has new tuneup, fuel filter

    2003 Chevrolet S-10 3 Dr LS 4WD Extended Cab SB


    Maintenance & Repair

  • 1999 Subaru legecy decelerates then stops. 5 answers

    Just purchased for my 16 year old high miles well maintained subaru legecy, had fuel pump replaced 2 months ago and it has a new battery. last night while my 16 was driving home, the car decelerated ...

    1999 Subaru Legacy 4 Dr L AWD Sedan


    Maintenance & Repair

Looking for a Used Cobalt in your area?
CarGurus has 7,526 nationwide Cobalt listings starting at $900.

Search Chevrolet Cobalt Questions

Chevrolet Cobalt Experts

#1 dandyoun
Reputation 640
#2 lightGear
Reputation 470
#3 MoGo
Reputation 390
View All

Related Models For Sale

Used Honda Civic"
842 Great Deals out of 57,416 listings starting at $995
Used Ford Focus"
1,760 Great Deals out of 64,013 listings starting at $995
Used Chevrolet Malibu"
1,602 Great Deals out of 73,975 listings starting at $855
Used Ford Mustang"
1,048 Great Deals out of 25,761 listings starting at $1,329
Used Chevrolet Impala"
1,731 Great Deals out of 59,300 listings starting at $995
Used Nissan Altima"
1,544 Great Deals out of 80,582 listings starting at $995
Used Honda Accord"
1,251 Great Deals out of 66,123 listings starting at $1,000
Used Pontiac G6"
447 Great Deals out of 8,024 listings starting at $2,499
Used Toyota Corolla"
1,207 Great Deals out of 54,848 listings starting at $995
Used Chevrolet Cavalier"
32 Great Deals out of 2,143 listings starting at $750
Used Mazda MAZDA3"
564 Great Deals out of 30,310 listings starting at $2,490
Used Ford Fusion"
1,753 Great Deals out of 69,802 listings starting at $2,995
Used Volkswagen Jetta"
1,077 Great Deals out of 37,069 listings starting at $1,995

Used Cars For Sale

2006 Chevrolet Cobalt LT For Sale
13 Great Deals out of 214 listings starting at $1,795