Hard start after refueling - no codes

[Junior Truck]

So I have a 2106 3.6 Colorado. She's been flawless for 65,000 miles.  Now I have two issues that I hope are related. With the absence of codes I'm looking for anyone who may have had a similar experience.  After refueling when the tank is real low (reserve light on) she cold cranks for several ignition switch cycles before starting.  This ECM has not thrown a code to date. No CEL. This only happens after refueling when the tank was really low. Kinda scary 500 miles from home. Maybe a stuck evap solenoid?  About the same time this started, I started to get a low idle stumble after running at interstate speed.  The low idle stumble is also intermittent.  Again no codes.  Was just bragging to a Ford guy about how reliable my Colorado and my Duramax have been, then this!  Anyone have anything on this?

[patrickjlindsay]

Hey, one year later and I find this!

My truck has the low rpm stumble too. I've been chasing EVAP issues. To date I've changed spark plugs, MAP and MAF sensors, O2 sensors (position 1 on both sides), the gas cap, and the solenoid in the EVAP canister. My issues started at 95k and have been lingering and I'm nearing 120k now. I have a 2016 V6.

For codes I was getting the code for a lean condition on bank 1, but that stopped after the MAF, MAP, and O2 sensors. The gas cap stopped the Tighten Gas Cap message, but now I'm getting an occasional P0455 code.



Have you fixed your truck? Did you ever solve the rpm stumble? What have you changed or checked?

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[tlaw91]

Hey, one year later and I find this!

My truck has the low rpm stumble too. I've been chasing EVAP issues. To date I've changed spark plugs, MAP and MAF sensors, O2 sensors (position 1 on both sides), the gas cap, and the solenoid in the EVAP canister. My issues started at 95k and have been lingering and I'm nearing 120k now. I have a 2016 V6.

For codes I was getting the code for a lean condition on bank 1, but that stopped after the MAF, MAP, and O2 sensors. The gas cap stopped the Tighten Gas Cap message, but now I'm getting an occasional P0455 code.



Have you fixed your truck? Did you ever solve the rpm stumble? What have you changed or checked?

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You need a purge valve. Highly common.

I hope this helps

-GM Technician


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[patrickjlindsay]

I've changed the one on the intake:
https://www.rockauto.com/en/catalog/chevrolet,2016,colorado,3.6l+v6,3315153,exhaust+&+emission,vapor+canister+purge+valve+/+solenoid,4936

As well as the vent solenoid on the vapor canister:
https://www.rockauto.com/en/catalog/chevrolet,2016,colorado,3.6l+v6,3315153,exhaust+&+emission,vapor+canister+vent+valve+/+solenoid,16992


I forgot to mention I've changed it already. I think I'm going to have to smoke the system to find the leak.

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[steve841]

No help, but when I was young and owned nothing but garbage, I got stuck at many a gas station.

 

This taught me a valuable lesson:  I never ever shut off my vehicle when refueling. 

 

Yeah, you're not supposed to, but I've never been stuck again.