1994 GMC Sonoma Idle/starting issue

[Kthkjr]

Hello, hopefully someone can help me cause im pretty stumped at this point with my issue. My truck starts fine the 1st time i start it in the morning, but after about 10-15 mins of driving it starts to go up and down on the rpms to the point where when i idle or coast it will sometimes stall if not it comes real close to stalling. Also after running it for 10-15 mins when i go to start it again it hesitates as if its not getting enough fuel, if i press the gas as im starting it it seems ok. One other thing to note is i can smell gas from the exaust to the point i thought i had a leak. Ive checked my fuel line and its fine(no leaks) ive also relplaced the fuel filter, o2 sensor, fuel pump and have done my cat/wires and plugs. Fuel pressure seems fine also, when i replaced my filter it wasnt totally tight so i had to redo it and the pressure was pretty intense, had to slow drain cause it wanted to squirt/spray every where. I do have a small head gasket leak which i know i need to replace but im hoping thats not the issue. Any help is appreciated and if you need more info let me know and ill do my best thanks in advance. Also ive check the engine for vacuum leaks and i cant find any.