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i checked for fuel trim improvement with pcv hoses blocked and had no success. So my oil is not contaminated enough. truck still runs rich.
I made some wiring checks for bad grounds and couldn't find anything wrong but Im not very confident with electrical tests made. maybe I 'll try again.
I like what you said that the coil fails after driving for a while. Indeed the truck seems to run worse after longer period of driving.
Fuel pressure drop is very very slow. I dont think it is a problem.
Like I said its my first time fixing a car. I studied a lot but i dont have any experience. any suggestion helps. thanks