just wondering...........

**astyles** · 03-29-2006, 08:44 PM

i have a 2001 z28 with 102000 miles on it,i have had it about two weeks and wanted to know about the rattling sound at 15 to 1700 rpms(between shifts)from the engine,it is a a4 other than that i love this car! it hauls ass....it has 2 chamber flow master and it apears the airbox has been opened up on the bottom....i got it from a credit union car lot so they really had no idea about anything with the car as far as mods.

**RainMan** · 03-30-2006, 03:13 AM

Common LS1 & F-Car Noises I've noticed or heard about:

Lite Engine knock that is consistent with rpm. Starts about 30 sec or so after start up at idle and go away after engine is fully warmed up? Probably LS1 Piston Slap.

Under car rattle while driving or idling? Could be exhaust rattle. Check rear exhaust hangers that may be worn out, check hanger near end of tranny, check for loose heat shields above and around the cats and "Y" pipe. Check all along exhaust for places where it may contact body or other components. Check for loose or worn hardware, bolts-n-such.

Drive train vibration / rattle / rear end howl, Check for worn/broken rear rubber transmission mount. Worn U-Joints. Howl, Worn rear end/excessive backlash, low fluid.

Pops, squeaks, and the like from roof, T-Tops, doors, and hatch, could be from body flexing.

Just check the car over real good, 102K miles for an '01 is a tad high. Might have been a DD or a highway car, who knows?

My '02 WS6 has around 24K & had a few annoying noises.
LS1 Piston Slap, unresolved, minimized with Royal Purple. . .So far. .
Slight rear end Howl, resolved, fluid change, thicker viscosity
Body Flex, resolved, Sub Frame Connectors and Strut Tower Brace.

Welcome to the Forum and Enjoy your ride!

Later

**astyles** · 03-30-2006, 08:07 AM

the only time i notice it is under lite exceleration(leaving stop sign)just as it reaches 1500rpm till it shifts at 1700........it does sound like it is comimng from the engine.

thanks for the responce and advice!

**keliente** · 03-30-2006, 12:31 PM

With an '01 car there's a good chance that it is spark knock...plenty of folks have problems with 01-02s consuming too much oil via PCV, which then dilutes the a/f ratio and makes it run too lean (spark knock). Not sure if that is the kind of 'rattle' you are hearing or not.

**astyles** · 03-30-2006, 12:34 PM

i am gonna do the catch can next pay day.....maybe it will help....

**RainMan** · 03-30-2006, 01:15 PM

Originally Posted by keliente

With an '01 car there's a good chance that it is spark knock...plenty of folks have problems with 01-02s consuming too much oil via PCV, which then dilutes the a/f ratio and makes it run too lean (spark knock). Not sure if that is the kind of 'rattle' you are hearing or not.

Good point, I guess I'm one of the exceptions, mine doesn't use any oil. . . . .yet!

Good Article on Detonation vs Pre-Ignition:
http://www.streetrodstuff.com/Articl...ne/Detonation/

**SeVeReDiStOrTiOn** · 03-30-2006, 08:34 PM

Could be all of the above....and also check the o2 sensors. The stockers come with a little metal o-ring thing that is on the bottom of the sensor and attaches to the wiring heat insulation. I had 2 that were rattling all to hell when I first got my car, and your symptoms are identical to what mine were. If that's the prob then you can either replace them or put some black rtv sealant between the metal thingy and the sensor.

Start small...and then look for bigger probs if need be