Motor revs up since i replaced knock sensors on 2003 chevy siverado 5.3 like its getting wrong message for throttlebody

what is question --motor size -- the following link shows info on knock sensor may help if not either resend or edit question with additional information 2008 Chevy Tahoe suburban yukon silverado sierra avalanche 5 3 knock...

Nathan, 2 Knock's are located under intake manifold.
Check the attached links,
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How To Install Replace Engine Knock Sensor 2000 06 5 3L Silverado Sierra...

Knock sensor 5 3 4 8 6 0 replacement

05 Chevy Avalanche Knock Sensors

4 8 5 3 6 0 knock sensor replacement GM

take to autoparts store, have them pull trouble code, have you replaced the OXYGEN sensor ? do it ! whens the last time you replaced both the AIR & FUEL filters ? do it ! find out code, its probably a sensor ! oxygen, like I mentioned . the MAP sensor could also be fauty . anything to do with air & fuel delivery !!! VACUUM lines, check them all, replace as necessary, TIGHTEN the mounting bolts to THROTTLEBODY, maybe the gasket is leaking ! put fuel injector cleaner in tank, next fill up . when you replaced distributor, did you replace the spark plugs & plug wires ? very important !!! EGRvalve, this valve gets clogged up severely choking the engine on these trucks !! pull it off, take a look, clean it or replace it ! when you set timing, did you follow the manual, some require you bypass the EST system, by unplugging its connection . (electronic spark timing). usually located @ firewall, under relay cover. replace the knock sensor ! todays fuel is BAD for your truck, you may think you have a miss, when you inturn have a "spark knock" , replace knock sensor @ engine block ! I think we covered it, balls in your court, hope I help you , its never just one thing, truck needs a maintenance day !!!!!!!!!

Have a factory or professional scanner hooked up , check for DTC'S - diagnostic trouble code's .GM had problem with stepper motors in side the instrument cluster ,model years 2003 to 2006 . Stepper motor's control the gauge needles .
How to repair GM Instrument Cluster Speedometer Gauge Stepper

The ABS an service brake message or probably related , have it checked for code's !

Hi, the knock sensor helps the computer optimize ignition timing and yet avoid detonation. When the sensor fails, the computer defaults to a timing that is less fuel efficient. Replacing a knock sensor is usually easy, provided there is access under the engine. Depending on which engine you have, it's usually centered on the block just below the cylinder head. There is one sensor on each side, and the trouble code should have indicated bank 1 (driver's side) or bank 2 (passenger's side).
Please let me know if you have more questions, and thanks for using FixYa.

Typical knock sensor:

You have two knock sensor's, both sit under the in-take magifold on top of the engine, you will have to remove injector rail and in-take.

These sensors are quiet a problem. They are located under the intake and normally go off because the engine got washed sometimes the water will evaperate and the problem goes away but anymays the intakes gota come off there are 2 of them so i would recomend replacing both while ur at it

The knock sensors are located in the rocker valley underneath the intake manifold. GEt a hynes manual to assist you in replacing them. There is acertain tightening sequence when taking the manifold on and off. It is made of a composite plastic so use care and do not over tighten.