'14 Hatchback sputtering and stalling out

[rjhodgefamily]

So recently for the last 4 months or so my Sonic has been sputtering and stalling out about once a week. Always when the tanks is somewhere between a 1/4 and 1/2 a tank of gas. And always after sitting in the hot sun all day. Never in the mornings.

I had the P0171 cracked intake hose for awhile which was causing my gas mileage to tank to down around 23-24. Once fixed mileage climbed up to 27ish but never back to the 32 I had before the intake hose cracked. And then This started happening back in January but never any codes or check engine light from the stalling.

That is until today. Today it stalled out and threw out 3 codes. P2076, P2070 Pending, and P2076 Pending. The car has roughly 62K miles on it. And in my limited car knowledge just not sure what I should do to fix the issue.

Any Ideas? If you want more info just let me know andI can dig it up.

 

[rjhodgefamily]

Sorry Left off what the 2 Codes meant.

P2070 - Intake Manifold Tuning Valve Stuck Open Bank 1
P2076 - Intake Manifold Tuning Valve Position Sensor/Switch Circuit Range/Performance Bank 1

 

[rjhodgefamily]

So last night I took apart the intake hose and cleaned the throttle body with some CRC Throttle Body and Intake Cleaner. The butterfly did not appear all that dirty just a little bit of carbon on the edges. After I was done with that I went ahead and ran a can of CRC Intake Valve Cleaner through the engine and reset the codes.

This morning the car is running better (33ish mpg) but immediately threw the P2076 code again. Just not sure what to do at this point.

I was going to try a new MAF sensor that I have in the box still from when I was having the issues with the air intake host but for the life of me I couldn't get the old one disconnected.

Should I even bother with the MAF or should I just look into a new throttle body or intake manifold?

 

[Chevrolet Customer Care]

Hello rjhodgefamily.
We regret to hear that your are experiencing this concern with your Sonic and can certainly understand your frustration. We recognize that you are taking a diy approach, however, we'd be more than happy to assist if you would like to have this concern addressed at the dealership. Please send us a private message with some additional details if this is something you are interested in.
Netty J.
Chevrolet Customer Care

 

[rjhodgefamily]

So I am beyond the DIY approach at this point. I swapped the MAF last night and reset the codes. Got the same check engine light this morning. It is going to have to be something in the Throttle Body or Intake Manifold. I just am not sure what is covered by the 100k Powertrain warranty.

Throttle Body is something I am comfortable swapping but the Manifold is definitely not something I would like to tackle. But if these parts are covered by the powertrain warranty or the extended warranty on the Intake Hose (that I replaced myself prior to Chevy notifying owners) then I would be happy to take it to my local dealer.

As I have been driving the last couple days I have noticed that it does idle pretty rough. Not sure if that helps to diagnose the issue or not.

 

[RMinNJ]

Maybe that orange pcv valve thing in the intake manifold is gone ?

 

[Aftermath86]

If it only happens after the car sits on a warm day after start-up, it might... stress might be the EVAP purge control solenoid. I had nearly the same problem except it sputtered and stalled right after filling my gas tank and after the car sits on a warm day. It's a very simple go-no-go test to see if that's it.
I'll post pictures later on too but all you have to do is locate the solenoid and start the car. Then remove the hose connected to the purge canister, not the engine side, then place your finger over the port and see if you feel a vacuum. It might be in a purge condition so do it for about a minute. If it continues you have a bad purge valve. Thankfully it's very simple to change out and it's only 20 bucks from a dealer.

Sent from my ASUS_Z01BDC using Tapatalk

 

[Aftermath86]

Seafoam I'm the intake manifold thru the brake vacuum boost house works wonders too for cleaning out the manifold. Just read the directions, carefully.

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[rjhodgefamily]

So would the EVAP purge control cause the EVAP monitor to not reset as well? Since the last reset of codes that is the only monitor that has not flipped to ready.

 

[Aftermath86]

That monitor is very finicky to begin with. It requires you to have between 3/4 to 1/4 tank of gas above 40 deg F and idling for I believe 5 minutes for that to be ready. Either way if you haven't taken off the (-) battery terminal lately that should be okay. It would make sense that the valve would cause that particular system to not be ready.

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[rjhodgefamily]

Aftermath thanks for the tip on letting it idle for 5 minutes. That got the EVAP monitor to reset. I'll test the EVAP solenoid when I get back home.