I have an 04 silverado with a 5.3, sts turbo, 43lb injectors,255 walbro, 5lbs of boost and only rev's to 5000 in first and about 4500 in second?? after checking everything we could think of the tech's now think it is valve float?? The truck now has 6000 miles on it and 5000 when the turbo was installed. Anybody else ever had or heard of this problem with a stock engine?? Allen Nelson tune that appears to be right on.

 

sounds more like a fuel delivery problem to me (fuel filter?) i don't think you are having valve problems.. The other thing i have seen is problems with spark like spark blow.. but it sounds like ignition or fuel to me. Also is boost dropping off at all?

 

The tech's at Xtreme checked it with laptop ect. said fuel is ok. It is the returnless fuel system and no replaceable filter as it is in the module. Blew the fuel lines out from the motor to the tank with tank removed and nothing.

 

oops didn't catch the 04 part... Valve float is a possibility, what kind of noise does it make. Does it just fall flat on its face? does it keep climing?

 

Just falls on it's face and it does sound like valve float.

 

Get a set of 918 springs installed and you will be fine.

 

Did you have the same problem? where do I get the 918 springs?

 

Anybody know where I can get a set of 918 valve springs?

 

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i agree about the springs