I have a 2013 Chev Utility Ute 1400 Petrol (Montana elsewhere) in South Africa. GM have pulled the plug in South Africa and I'm having difficulty getting my problem solved by the local GM appointed agents, this has been on-going for the past 3-years. Here goes:
When I start the pick-up it rough idles and you need to wait 10-15 mins then it miraculously corrects itself (you can feel the engine change), during this time there is no power to drive it. This is an intermittent problem and can happen 3 /4 times per month when the pick-up is hot or cold, its exactly the same symptoms every time, you just have to sit and wait. We have replaced the oxygen sensor, engine coolant temp sensor, fuel vacuum cannister, accelerator pedal sensor, cleaned and serviced the throttle body, updated the software, diagnostics show no errors.
I would be extremely grateful if someone out there could offer some help and guidance.

 

You may need to replace the MAF and MAP sensors or clean them. You can get the cleaner(s) at a parts store and follow directions completely. When I looked up the parts I did not find the exact application but you will have to pin point that yourself. You also gave no engine size so again, I guessed at a 5.3L engine. You gave no mileage either. You can likely order parts from here in the states from Rock Auto, where I got the links from. You also gave no history for tune related parts like plugs and wires. You should also get a fuel pressure reading.


MAF sensor: https://www.rockauto.com/en/moreinfo...000997&jsn=908 or the MAP sensor: https://www.rockauto.com/en/moreinfo...000997&jsn=950 or both. These can cause the same intermittent problems.

 

Please be more specific about “fuel vacuum canister.” I’m guessing you mean the vapor canister back by the tank, but since you’re in South Africa the emissions set up could be different than a US model and it’s important we understand each other.