IIILuisIII

iTrader: (1)

Owning an LS1 must be a love/hate relationship for everyone else too unless your motor is quiet.. Mine has piston slap.. a slight clack clack that i notice in the drive through sometimes.. a noise that sounds like a giant salt shaker filled with pebbles when the rpms come down (posted in a thread and was told its normal).. but i've noticed a loud rattle sometimes when i give it sudden throttle. By sudden throttle i mean i can be cruising at abt 30 mph and gas it alittle to speed up to 40.. and for a split second it will make a loud rattle that sounds like its coming from under the car maybe between the front wheels. it wont rattle the whole way to 40 but just for a split second. I feel no loss in power or anything, no hesitations everything seems normal.

Thanks in advance for the help

Edit: almost forgot.. The car is a 2002 Trans am ws6 A4 mods are SLP intake and magnaflow catback.

joecar

If it's spark knock the engine will make a distinctive rapidly popping popcorn sound while you lay into the throttle... if you log with a scantool it will show Knock Retard. Also check the intake manifold for oil being pulled in via PCV plumbing (lowers effective octane and allows spark knock).

If it's a rattle coming from under the middle of the car, it might be the y-pipe/i-pipe joint rattling from the i-pipe ID becoming loose.

CHADsterss

Is it sort of a metal sound? If so It could be your exhaust... I had the same problem with a lose exhaust flange on the driver side after the cat. (Stock manifolds)

IIILuisIII

iTrader: (1)

Hey its been a while but there was oil in the intake. Changed the pcv valve and gave it a tune up and also ran seafoam through it and still getting the spark knock.. Do i have to take the intake off and clean it?

chrisfrost

iTrader: (8)

I'm not going to speculate because there are alot of possibilities but I will tell You this ,,,,if it is piston slap Your'es is a little worse than most .

IIILuisIII

iTrader: (1)

Def not piston slap. checked with android app torque and its pulling timing everytime i hear that noise.. Its not constant, only when i give it sudden blips of throttle at low rpm and sometimes at wot you can hear it pinging

Troy5061

iTrader: (19)

Mine was spark knocking when I bought it, the ECM was commanding 10.5:1 but my wideband was reading 15:1. Turned out to be the MAF sensor, I don't know if it was K and N oil that did it or the guy that had it before descreened it and that caused it. Probably why the guy sold it so cheap, he must of thought it was fucked up lol. Went to speed density, problem solved

Z28Z06

iTrader: (2)

How is the gas mileage with speed density Troy?

IIILuisIII

iTrader: (1)

Just an update for anyone who searches these threads look for a solution to a similar issue.. it was the maf.. unplugged the maf when i read troys comment, have not had any pinging/spark knock at all. and I've been driving it ever since