Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Welcome. I am Cam. This is a sign that the injector nozzles are leaking a bit. AT idle the computer tires to smooth the idle out, so the injector timing changes for each cylinder, which is the balancing rate. When they leak, during idle they smoke a light gray white or black smoke. The key with this is at idle. This is typical. The diagnosis for this is to disable the injectors one at a time and watch the amount of smoke that is being produced. Any injectors that you disable that make a difference will need to be replaced. This fault was never covered under the special policy that GM put out.