Hey guy's just bought a 03 RCSB with a 5.3 and 3.42's,about a year ago i had a 02 RCSB 5.3 with 3.73's,my question is the 02 would smoke this 03's ***,it's like night and day,I would'nt think the 3.73's would make that much of a difference,both truck's are completly stock,just looking for some input in the difference of these truck's,also the 03 is throwing a knock sensor code how bad does this effect performance.Thank's guy's any input would be a great help.THANKS!

 

If it's throwing a KR code it is probably running on the low octane table so you timing is probably much lower than what it should be. This could be some of you the difference in power you feel along with the difference in gears. How many miles are on the truck?

 

80,000

 

It has a little to do with the gears, but you could be running shitty gas or something. If they are completely stock then also it's the settings in the pcm, it might be the same 5.3 but things change from year to year. Different shift point settings, maybe added timing idk. Someone will chime in that knows more between the two year's settings.

 

I would find out what is causing it to throw that KR code first. While that's not real high mileage for these engines or anything your cats might be starting to get plugged, especially if the truck has been running lean, that will also hurt performance. I was pleasantly surprised when I installed my headers and removed my cats at how much smoother it runs and how much less throttle is needed to cruise on the highway.

 

I agree, you need to find out why ur getting KR. Find out if anyone has hptuners or something in your area or if you have a friend at a dealer or something to find out what is goin on with the motor.

 

I agree...the converters could be clogging up, and this will make a hefty diffrence in performance of the truck.

 

I've heard somewhere that the 02's were the fastest stock trucks. They were less restrictive in the tune than the other years. In 03 they added in more TM or something. Somebody back me up.

 

That is very much possible

 

The knock sensor code is commonly from a bad sensor or bad wiring. That will command 8-10º of timing retard any time you are at wide open throttle. Fix that and you'll find that the 03' should be roughly just as quick as the 02'.