While in park/idling being hot or cold, if I hit the gas I feel and hear a slight hesitation. In drive I don't really feel that hesitation it may be so slight in drive.
I was going to change these parts anyway, I replace the MAF, throttle body, K&N filter, major tune up iridium plugs new wires etc. Been this way since I bought it b4 I did all this. Help

 

I did not know that the spark plug wires were a replace type item?
Did you use the oem spec spark plugs?
Did you replace or clean TB?
as for the MAF ....oem, ACDelco or parts store?

 

The I5 has now spark plug wires to replace, it uses a distributor-less coil on plug pack ignition system.

If you used anything other than AC Delco spark plugs with your I5, they will not last and will cause problems after as little as 6-7K miles.

When you say hesitation, do you mean you feel and/or hear the engine stumble? Or you just sense a delay between throttle movement and response?

Keep in mind, these trucks are all fly by wire (no throttle cable connected to the gas pedal). When you press the accelerator, the accelerator pedal position sensor - PPS- sends that movement increment to the PCM, which then has to send a command to the Throttle Body to move the throttle, which then has to be measured and confirmed by the Throttle Body Sensor -TBS and sent back to the PCM before the engine responds. While it is all blazing fast, there will always be a delay between when you move your foot and the engine responds.

If you engine stumbles... see this: https://www.hummerforums.com/forum/h...what-do-33916/