I have several 1999-2002 silverados. I have a 2000 ext cab auto 5.3 chevy that is gutless compared to my other 2000 Silverado with 5.3 and even my Silverado with the 4.8 is considerably more powerfull than this truck. the other two trucks are reg cab so weigh less but how much of a difference would this make? the difference in power is very noticeable yet the truck runs fine. does anyone know why?

 

Weight makes all the difference, even teh same truck that is 2wd vs 4wd will vary many many truck lengths in teh 1/4 mile.

The 1999 engines were the lowest rated at 270hp/315 lb/ft, compared to teh previious 255hp/330 lb/ft L31 Vortec 350 and the later 5.3 rated at 285hp/330 lb/ft.

SOme of the 1999/2000 trucks have PCM's and Operating Systems that are notorious for false knock issues. We are talking about trucks that are now 15 model years old, there is bound to be soem age related differences at play.

peace
Hog

 

If you can get your hands on a good scan tool, take a look at your knock sensor activity, and take a look at your fuel trims. If the fuel trims are high positive numbers on both banks, test your fuel pressure. You may have a weak fuel pump or a bad pressure regulator. If your knock sensors are showing a lot of activity during normal driving, the sensors may be failing due to age or corrosion. If you end up replacing the knock sensors, be sure to also replace the harness, and seal the grommets with RTV to prevent future issues.

Those are just the first two very common issues that popped into my mind.