Good morning y’all. I have been experiencing something kind of weird with my newly purchased ‘99 Tahoe 350 4WD. Let me start by stating I am not very familiar with automatics and have mostly owned/DD’d manual transmissions. The thing I’m noticing is that when I’m driving around and let off the throttle the RPMs drop to about 1-1.4K and feels like truck is still lightly throttling. Usually after some braking the RPMs will drop to the sub 1000’s. Kind of curious what might be causing this? I’m not hugely bothered by it other than it forces me to brake harder in certain situations. My friend mentioned that someone might have advanced the timing a bit. He mentioned that based on that RPM weirdness and the fact that the truck kind of starts like a race car. When you start it, it almost feels like either the battery or starter are getting tired. Kind of sounds like it struggles to to start for a couple seconds and then fires right up. I have no idea either way and would love some thoughts on the subject. Thank you.