I don't know anything about the EGR Valve, but every time I buy a new vehicle I do the following:

-PCV
-Oil and Filter
-Trans Flush
-Coolant Test
-U-joint inspection
-Spark plugs and wires
-Run the codes

I have been told by multiple sources that plugs and wires don't matter, but I am convinced that my vehicles run better afterwards... and I don't like to take any risks with the combustion.


As far as your clunk goes, I would have another chevy owner drive your truck, or drive theirs. The "chevy clunk" is a time honored tradition among chevy trucks that I really thought would have been fixed in recent years. Nope. My 2013 at 28k miles has the "chevy clunk"

 

Thank you... All of which I plan doing in the near future.

 

WELL...HELL's Bell's, After getting around to changing out the original radiator fluid last week, (what a job) and it still ain't clean enough for me though. I changed out the plugs and coil wires. First I wish I could of afforded better plugs, but I did get oem plug wires. long story short; after I replaced the plugs and wires, it ran like a bat out of HELL... so, all my assuming the worse was for nothing. it ran great! ran it up to 5K several times. kicked it down into passing gear a few times and it ran great. That little 5.3 can really move the 6000 pound beast. I guess them plugs and wires must have been original like everything else on it...
Thanks for your time.

 

Glad you're up and running!

I was a little disappointed when GM discontinued the 5.7- they have a habit of fixing what isn't broke... like scrapping the Bonneville and Grand Prix for a g6 LOL

...but the 5.3 is an awesome engine... even if they aren't maintained!

 

I can only agree with you...
my motto is " If it aint broke, fix it until it is!"