I have a 2002 Silverado 5.3that has progressively gotten lower and lower on power. I have been getting a "service engine soon" message also. It seems that the engine is starving for fuel or air with no get up and go at all. I replaced the fuel filter and spark plugs withno change at all. Does anybody have any suggestions or this same experience?

 

What code is it throwing and what mods have you done?