2000 Silverado 1500 5.3L

Well seems like everything is going at once.

Just finished a new fuel pump and new belts because a year old AC belt crapped out and took out main belt with it.

Now I am getting message for Knock Sensor #2

How involved is it to replace. I know I have to pull or lift up the intake. So that does mean I have to disconnect fuel lines? Is the intake dry? I know the TB has coolant lines to it. I guess now would be a good time to clean TB and do the coolant bypass mod. Will I need new intake gaskets?

This is the first time I have been this deep into an LS motor. I have done the usual outside motor things like water pump replacement, I feel confident in replacing the sensor, just wondering about any tips or any possible OH CRAP.

Unbolt throttle body lay it over it will take a little nudge disconnect fuel lines need a plastic tool for them undo bolts undo vacum lines and sensors pull intake swap knock sensor which is probably going to be completly rusted I usually replace gaskets when I do them at work

How many hours to do the job?

2-3 hours if its your first time,its really a pretty straight forward job.

Sounds great!

i would also recommend replacing both knock sensors and a new harness

It's not too bad.  Fuel line needs to come off, but you can bleed it out by using the schrader valve on the rail.

I replaced both sensors and the harnesses at the same time, and then literally smothered the new sensors in RTV... basically made a little valley around each of them to keep debris and water out.  That's the big reason they fail initially, is poor isolation from elements. fwiw I did that 100k miles ago and haven't had a problem since on it.

I'd be surprised if you spent more than a few hours doing it.  JUST DONT DROP ANYTHING INTO THE HEADS WITH THE MANIFOLD OFF.

Ask me how I know.

That is why I use painters tape to mask the ports as soon as I remove an intake.

Thanks for the tip on replacing the harness, I had already planned on replacing both sensors.  

Already over 200,000 miles I refuse to get rid of this truck it has been so good to me. I guess the body is going to have to fall off before I give up on it. The way the body looks that might be forever.

This.

Yep easy peasy.
Get both sensors and a new harness, and build a 1/4" wall of RTV around the knock sensor holes to keep water out. You will lose a little cooland from the throttle body, and you will need new intake gaskets. That engine has a tendancy to develop vacuum leaks at the intake gaskets anyway so you are doing yourself a favor.

If it were my truck and the knock sensors wernt rusted to shit, I MIGHT only do one sensor and skip the harness, but the above is the only way we do them at the shop.