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.