Alright here is a good question (at least I think so)

2000 Sierra 4.8L SCSB 4X4.

The only engine mods I have done to it right now are:

HyperTech Tuned (87 Octane) + other programming
K&N FIPK Kit
FlowMaster Duals (70 series)

Do any of you also recommend another thermostat? I still have the stock one.

I am noticing a lot of spark knock and a friend of mine said I needed to change to the plugs.

What plugs AND wires do you guys recommend.

I want a little better throttle response + NO MORE SPARK KNOCK! It sounds like a diesel after it warms up.

Thanks,
GatorFan

 

You might just need to run a higher octane in it. I would go back with the stock plugs and go with a 160* thermostat.

 

I run the Taylor Thundervolts plug wires and NGK plugs.

 

I'm with Rhino69 on this.
Try a higher grade of octane fuel first. I don't know why some of you guys just don't look at the big picture on this filling up with 87 oct or 93 oct.
It would only cost you between $4 & $5 bucks more to put the highest octane grade fuel in over the lowest oct fuel. Surely if your into performance 4 or 5 bucks more a fill up is not going to hurt you.
That's my perspective on that.
Anyways, try the highest grade fuel first. See if that helps the clatter.
How many miles are on your truck? I use to have a 2000 5.3L ECSB Silverado with Hypertechs 93oct tune in it. It worked great until around 120,000 mi, and it started to clatter a lot upon acceleration. I also replaced my plugs and wires at 100,000mi with NGK plugs & MSD plug wires.
My miles on my truck were all hard miles. The clattering was there to stay due to worn internal parts. Probably more the timing chain than anything.
I also used Mobil 1 full synthetic oil in it as well when it reached 50,000mi.
Try these items: replace plugs with NGK units, and wires with MSD units.
Also switch to a higher grade fuel.
Use a good fuel treatment, replace fuel filter, replace PCV valve, have the injectors flushed, and buy a throttle body cleaner to clean the inside of the throttle body, and only spray it inside the MAF meter(do not wipe the insides of the MAF meter).
There is no need to switch to a 160* T-stat with basic bolt on parts. It's not even hot enough outside yet for that to be an issue.
Also switch the Hypertech's program to the 93oct tune if you decide to start using the 93 oct fuel.
Your truck may just need a tune up. Those tune-up items listed above should cure your problem. If they do not, then there is just excessive wear on the internals of the engine. That would require of course a rebuild or at minimum a timing chain replacement.
Good Luck!

Jim

 

Yea go get you some NGK TR55's they only cost me $1.50 each and then some MSD wires. and do what they said above /\...

 

Thanks for the info fellas. As far as the mileage is concerned. Well, I only have 37,000 miles on it. Thanks to being in the military and deployed ALL THE TIME! Anyway, I tried using higher octane before but I didn't notice much improvement. It could have been just a batch of crappy gas. I'll switch the HyperTech to 93, and switch the plugs/wires and let you know. I plan on selling the HyperTech pretty soon and have Nelson Performance tune my ride. I have heard nothing but good things about this place and it IS right around the corner.

Also, I saw that one of you guys are using a Throttle Body Bypass kit. Do you see any gains at all. I know it's a cheap upgrade so I figured I would ask. I posted this same thing in another thread. I figured that here is Texas (during the summer) it would help on cooling the air entering my TB.

Thanks for the suggestions and info.

Later,
GatorFan

 

Try a mid grade fuel
Those ngks are good to replace the plugs with, while your at it go ahead and replace the wires. There hasnt been signifigant gains in going with msd or taylor or whatever.. i would just get some basic stock wires. The extra money isnt really worth it IMO.

The tb bypass doesnt really do much... but DONT BUY THAT KIT. All you need to do is take the inlet hose (right hose on the bottom of the throttle body) and connect it to the outlet hose (left hose on the tb) and completley by pass the coolant from going through the tb. Its an easy concept, it will keep the intake charge there a bit cooler but nothing signifigant. Also, when connecting those two hoses togetther, the inlet and outlet hoses, use two hose barb ends that will fit in the ends of the hoses and just use hose clamps to keep it togetther. Its a $3 trip to the auto parts store compared to $15+ for these kits they sell on egay.

Good luck.. if you need any help PM me.

 

I didnt have to use the connector, my hose was long enough to replace one of them completely.

 

My hose is longer than yours!!!

Jim

 

If you only have 37,000mi, then your internals are still in top condition.
It's hypercraps tunning they use. It's just an average tune, it's not tuned per individual vehicle like that of a Nelson tune.
I would change gas stations. I have always had good luck with Shell.
If your going to step up fuel octane grades, then just step up to 93oct. Especially if you decide to go with a Nelson tune. You get to have more timing advancement than with using lower oct fuels. Nelson will tune your truck to how you will use it primarily and to your mods.
If you have been using cheap gas lately, go a head and buy you a can of Berrymans. It's in a metal can. It's one of the strongest gas additives out there. Place that entire can in your gas tank and fill it up with 93oct fuel.
It will clean your injectors, valves, tops of your pistons, and combustion chamber.
Leave the factory plugs & wires in for now. They still have plenty of abuse left to them. You will see no gains from replacing them.
Don't remember, but do you have a CAI kit? If not, get one or at least replace the factory air filter with a K&N unit. Get a good cat-back exhaust system as well. Just helping you spend your money!
Get the Nelson tune as soon as you can. You won't regret it!

Jim