Hi guys,

This is my first time posting on these forums but I'm on here reading often. I had an 09 Cobalt that I bought 6 months ago until someone totaled me a few Sunday nights ago. I loved the car so much that I went and got another one just last Monday at a dealership about 50 minutes from my house.

This one is a 2010 with 70,000kms. It ran fine for the first few days I had it, and for the most part it still does. However, last Friday on my way to work, I was in 2nd gear not going too fast as I was following someone and just completed a turn. All of the sudden it felt like something slipped (not sure, but that's the best way to describe it) and the engine just started sputtering. It was almost like I lost all power. It went from like 50km/h to just chugging along for probably about 10 seconds. After those few seconds, it felt like it was running properly again - back up to regular speed. I'm always paranoid about something with the turbocharger, so I tried punching it really quickly when I realized there was no boost at all. I had the pedal to the floor and it just accelerated very slowly with no boost. On the drive home from work, after pulling out of the parking lot I punched it again just to see if what had happened earlier was just a hiccup - maybe having the car off and giving it some time would help. And, it did. It punched and boosted as normal.

Up until the other day the car had run fine, but yesterday on the way home from work, I was at a red light when the car began to idle roughly. Again, just sputtering. The light turned green and I went to accelerate and it just sputtered, again for just a short period of time, and then ran normally. Again, I tried punching it and there was no boost. I tried punching it again, and still nothing. Then I tried again, it everything worked as it should.

Later on in the night, after about a 2 hour rest, I had turned my car on only to see on the RPD (I always have it on my boost screen), there was something I hadn't yet seen. It read "no data available" and wouldn't register any boost even though the car was boosting as it should. After starting my car again a few hours after, the gauge was working as it should and so was the boost. I haven't seen this screen again since.

On the way home from work tonight, I was on the onramp to the highway when I started to sputter again - same as the previous two times. Short duration, sputtering and then regular. No boost, then boost shortly after. This time it happened when I was in third gear.

There hasn't been any CEL lights triggered (as of yet, anyways). I've only started researching this tonight and haven't quite yet found anyone with the exact issue I'm having, although there are similar situations. I'm hearing about , spark plugs, injectors and other things. I'm not sure how to tell if my car has been tuned, or how to know which tuning the car has, or if it is in need of a tune up.

If anyone has had this happen before or has any information or suggestions, it would be greatly appreciated as it's very frustrating since I just purchased this vehicle. I didn't get additional warranty from the dealership, and they only have a 30 day warranty on safety related issues. I don't know a whole lot about the mechanical side of vehicles, which is why I'm reaching out to you fine folks as maybe you can help.

Thanks!

 

Check those intercooler endtanks. Sounds like a boost leak. I'm surprised there's no codes.

 

I didn't think it would be a leak just because I had it sputter even in an idle. And I would say about 90% of the time it boosts fine. I'm not sure I've ever actually sputtered when I was revving high or boosting. But it definitely gives me something to look at! I'll have to have a look.

 

Evap?

 

Just because it hasn't turned the MIL on doesn't mean that there isn't anything there. If it was me I would scan the vehicle. Might find something in the freeze frame or history.

 

Is the car stock? what mods? Tune?

 

Not sure about a tune. As I said, I've just purchased this car a week ago from a dealership. I'm not so mechanically inclined, not sure if there is a way to tell whether or not the car has a tune or which it has. In terms of mods the exhaust has been done, not sure how far back. And there's an air intake and an intake for the turbo. The only real things I could see - I wanted one with no mods but I had to settle for little mods.

In terms of the computer spitting codes, I didn't realize it would/could unless the lights were triggered but I'll have to give that a look.

And what about evap?

 

Post a picture of the engine so maybe we can see what has been added.
Are you sure your battery is good, check it also because if it gets low it will give the computer fits, even the tune.
And some advice- if the car isn't running right then DONT kick it down to the floor for maximum boost unless you want to run the risk of blowing it up. 100% the wrong thing to do.
What does it boost to right now at wide open throttle?

 

I haven't checked the battery. As I said I've only had the car for about two weeks. Its a 2010 so I would imagine it should be okay but I haven't looked into it. I don't have problems starting or anything though, even on the really cold mornings. My phone isn't allowing me to post a picture of the engine bay right now but I will when I get home. It boosts to ~120-130kPa when at WOT.

It's been a few days since I have had any issues but tonight I was at a slow drive in second gear when it acted up again, this time it lasted longer. And then it would be okay and then start again. It's really weird/hard to describe. Its almost like something is being pulled, and when it's sputtering it's like something is dying. Almost like a pump sputtering but idk. I tried to boost it a bit, not to the floor but tried to register something on the gauge in 4th. I tried twice and it didn't go past probably 5 kPa. After the second time it worked fine, almost as if I had to clear something out of the way to get back the power. I honestly have no idea really how to describe what happens, I tried catching it on camera but it's not all that loud and you feel it more than you hear it. But it's basically a rough idle that just kinda pops up as you're driving along. And then you lose all power until basically it decides when it wants to boost again And run properly. And it seemingly doesn't seem to matter what gear - I've had it in N, 2 and 3.

 

I have just attached a picture of under the hood for this car. Really wondering if it is just a sensor - not sure though. These issues seem to be occurring more often than before. I'm not sure if there is a way to trigger the issue or if it really is just sporadic. But even in terms of my RPD not reading properly, this is happening more, also.


And while I was driving today, my RPD wasn't working, I noticed something: (possible was in my head but thought I would make note incase) With my RPD reading 'no data available' on my boost screen, it doesn't seem like the boost is really regulated. In second, it just boosts really quickly without even trying and then it just like, drops off. Same with third. Not sure about 4th+. But it works fine if I actually make it boost. Just thought it was weird that it seems super peppy while it reads 'no data available' and just thought it was weird that it would boost without even trying. It would just boost as soon as I switch to 2nd for a second or two and then drop down to regular acceleration.


Again, I'm not sure if anything that I've said has made any sense. I'm just merely noting things I'm experiencing. I've only owned the car for two weeks and I'm possibly just paranoid and looking for things, but it's all seemed really weird and hard to describe so I've done the best with what I could. Aside from checking codes (still no CEL, but I just haven't had time to see if it spits back codes yet), just wasn't sure if (and which) sensor could be messing with the RPD (if it is a sensor issue) AND causing my sputtering issue?


I'm hoping that with this picture, it may help a bit more. If anyone has any more light to shed, that would be greatly appreciated! I'm going to try and get a reader on it tomorrow after work.


Thanks!

 

I'm not sure if what Nova said was a test about the not going WOT.... If so you failed lmao.

Looking at the pic you posted of the car telling me it isn't stock, so it is hopefully tuned.

I wanna say check the valves and throttle body for carbon build up. I think that could be the hesitation you may be feeling.

Have you have it scanned maybe there is a pending code?

Also where about in Canada are you ?

 

What you were saying about the picture? Im confused. It didn't look stock to me, it didn't look like my 09.

I actually have an update from today. A CEL has now been triggered. However I took my reader out but it isn't reading the code - must be too old. I got some fuel injector cleaner with a water remover. Not sure if there is water in the tank or the lines but I read on these forums somewhere that there could also be condensation.

When I was driving to work today all was well until I was about 5 minutes away. Sputtered in first after a light and chugged the rest of my drive (normally I can have it calm down but not this time) and then it backfired, which I believe is the first time I had heard since the beginning of this issue. Later tonight after trying to scan for codes, I started it up and it idled really roughly. But then I drove it around for 30 mins and no problems.

Throttle body isn't connected to the RPD right? Just not sure if data not being available on the RPD sometimes is a symptom of this issue or another?

Also I'm in Ontario.

 

Just finally got the code read. P0101: Mass Air Flow (MAF) Sensor Circuit Range/Performance Problem.

MAF sensor? This is the only code that was triggered even in history. Would this cause the **** ups in the RPD not always reading also?

 

No, you have a boost leak.

 

Boost leaks trigger a sputter even during an idle? I've never really had problems Boosting, it just sputters driving around regularly.

 

99.99999% of the time the P0101 is a boost leak. When you're at idle it's a vacuum leak and can cause issues.

 

And vac/boost leak are interchangeable right? Any common places to check for the leak? Would a leak be the cause of all previously stated symptoms?

 

When I blew my upper chargepipe from the turbo (boostleak) my car was running like crap

 

Continuously or sporadically? How is that fixed? Just buy a new pipe?

 

Well I didn't drive very long after I stopped and reconnected the pipe and tighten it down again, but I will agree with ecaulk that code is usually a boost leak, I would start by checking all charge pipe connections and checking the intercooler for any cracks (to best check the intercooler the bumper has to come off)

 

I agree about the boost leak, Like snail said visually inspect and if you can't see anything, Then you will need a fogger/smoker to find the leak or make the home made tester that is in the how too section.

I'm in ontario as well I am located in Courtice, Its about 45 mins from Toronto, Where are you roughly?
If you are close I can lend a hand if your ever in a jam.

Also I will link you to Powells website, Just incase you want/need parts or even some work done to the car he is a great guy and the add bonus is he is located in port perry, Ontario and this will save you big time on the dollar and shipping costs. Powell Race Parts.com

 

Sorry, my internet had been down for a few days. Thank you guys for your responses. Snail, I had the mechanic quickly check over everywhere for cracks. Didn't get to the bottom of the intercooler but everything else seemed OK to him. We pulled the MAF sensor and it looked clean but we cleaned it again anyways.


I had also brought it back because my CEL was on again, so we checked codes. This time, however, two entirely different codes were triggered. Nothing about air flow or anything at all. I don't remember the exact codes, they were cleared before I could jot them down but they were for Cylinder 2 Misfire and Too Rich at Idle Bank 1. Not quite sure what this could mean now - if anything for air flow could trip these two codes without tripping the same code as before, or if it is an entirely different issue?


T-Fog, I'm in Kitchener.. about an hour West of Toronto. More or less between London and Toronto. That is awesome, thanks a lot for your help and links!


I've also attached a picture. I noticed this ticking sound the first night that I brought the car home and had the hood up in the driveway but I never thought too much of it. Since all of this has come to light, I've revisited it. I had the hood up the other day and was reminded of the ticking. It sounds exactly like a timer, each tick precisely spaced out. Every 1-2 seconds. My mechanic sourced it to the black piece that is pictured. He wasn't sure what it was, maybe something for the boost or fuel economy? It's hooked to the fuel line and exhaust.


Do you guys have any ideas of what next steps could/should be? Anyone have any information on what this piece is? What the new codes could mean? Other things to check, try, anything!?

 

Ticking is normal, that's your high pressure fuel pump.

I'd still be checking for a boost leak, there is a thread around here about how to build one and test the system. Normally Too Rick at Idle codes are the first indication an oxygen sensor is going out, but make sure there is no boost leak, and you could for good measure replace the plugs with stock AC Delco plugs. Then address the oxygen sensor.

 

What about the cylinder 2 misfire?

 

I would check the intercooler better. Is it stock? Aftermarket? Some of the hahn intercoolers had problems with the welds breaking and causing leaks. I would pull the front bumper to get a better look at it. The main problem is that your drawing extra, unmetered air in the engine. Which will throw your fuel trims off and also make it run like cap cause the o2 is trying to adjust for a bad airflow reading