Good morning,
I have this problem started two weeks ago until now.
I have 5.3 GMC Sierra 2010
In the begging I have changed the battery. After that, the engine light goes on, when i checked on it, it said misfire on cylinder#8. I have changed all spark plugs plus the wires, the engine light still on and when i checked on it it said the same, misfire on cylinder#8. But after that the problem has started.
When i want to turn on my car, the RPM, TEMP SENSOR, AND THE OIL SENSOR don't seem well.
The RPM goes up and down like several times and the car turned off, maybe for 80 times that day. I said maybe the air intake has some water inside and its wet, but i was wrong! I went for two shops and they didn't know what is the problem, i went to the gmc dealer to check on my car. They said i have to change the wiring harness, battery and battery cables, plus they aren't sure what is the problem comes from !
In addition, I have this video I applauded on YouTube
Problem when I start to turn on my car after 7+ hours - YouTube


after my car comes warm, every thing comes well, i drive it like it doesn't have anything. Some times, the engine light shows, after that i lose the power but it disappear at the same time, like the engine light flashing and sometimes when the engine light comes, the car turned off while I'm driving


My friend told me i have to change the battery cables, they don't give that much power for the car or it has running from the power.
My other friend he said i have to check on the intake, and the throttle , they are not sure ...

I live in Miami, Fl. If anyone knows any shops that they know how to solve the problem, please let me know !
thanks.