I am looking at getting a silverado SS with a magna charger and longtube headers.

The truck has 70,000 somehting miles on it and the charge has been on it for about 30,000 miles.

At idle the truck has a slight knock to it...not extremely loud but you can hear it.

I keep reading and researching that it could be the charger causing low boost and causing the knock...or it could be piston slap.

Now it's moderatly loud..you dont have to listen close to hear it...drove the truck around for about 30 and still didnt go away after the truck warmed up.

Only does it at idle..as soon as throttle is applied it goes away.

Could the charger or something else be causing this.

 

I've heard of superchargers knocking when the idle is set too low...don't think that it's the GM characteristic piston slap, as that usually goes away when the engine gets warm.

 

One thread only please.

https://www.performancetrucks.net/fo...d.php?t=459005