3406E warms up looses boost ?

[Rockyhill]

Mal4shtf honestly I’ve been leaning towards the ecm the only thing that throws me of is that it doesn’t throw any codes is it possible for that to happen also the engine is a 1lw fuel flows the the ecm for cooling and I have to add every once in a while when I’m coming from a dead stop and start going through the gears the rpm will be coming up truck will be building boost and all of a sudden it will almost act like a dead pedal I lose all pulling power I’ll grab another gear then it will go back to normal. I had the truck on the lab top while it has acted up and if I have the pedal to the floor it will read it at 100% throttle so I believe I can rule out the pedal