gmc 2010 Sierra 4.8l weird color under oil fill plug

[Harris0990]

Hello everyone this is my first time posting anything here but I’m a long time reviewer of post. So I apologize if this is written somewhere else but I can’t seem to find it. So recently like a week ago I bought a 2010 GMC Sierra 1500 4.8l crew cab. Well last the few morning when I have gotten in my truck to go to work my truck has been had to start it just cranks but doesn’t roll over until I hold the gas pedal down but then surges up and down sometimes dies then repeat but after that once I start driving it’s perfectly fine no miss no studer. I can even turn the truck off and it’ll start right back up it seems to do this only after about 4-5 hrs of not being on. Now I’m hearing a ticking noise that has started slowly but now has gotten louder it seems to go with the rpms but the engine drowns it out at a certain point. It sounds like it’s coming from the bottom of the motor more towards the passenger side. It’s not a pulley I have already tried that. I just changed he oil and noticed his reddish brown stuff under my oil cap. My oil was clean when I changed it there was no coolant in it the truck doesn’t smoke or knock I haven’t noticed any coolant loss or oil consumption but I’ve only had it a week. The oil does smell gassie but nothing to concerning. Any info that can point me in the right direction would be greatly appreciated. Thank you