Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Hello and welcome! My name is ***** ***** I can assist you with your question. Without looking at the vehicle myself it is hard to say what is going on. However, I can tell you my experience as to what could be wrong causing this issue you are explaning. First thing is the variable valve timing solenoid. This solenoid could be sticking intermittantly causing this slight hesitation you are talking about. Another common cause would be bad tune up parts or even a bad oxygen sensor.
There are also PCM updates to help with this sort of thing as well. Cleaning the throttle body may help and checking the electronic fan clutch might be worth looking into. (you can disconnect the connector going to it and then retest). Some fan control complaints can be misinterpreted as a running problem.
Another possible cause would be the mass air flow sensor. Ths computer uses this sensor for injector pulse width and it is a very important sensor. You can try cleaning it to see if that helps but it may need to be replaced.