Bizzles

iTrader: (3)

I started my car up today and decided to rev it after it warmed up for my weekly start up (car is not DD). I noticed right away that I was getting a small vibration upwards of 2k rpm. Could have always been there but mostly I slowly rev the car via the throttle body instead of sitting in the car. I proceeded to put the motor between 2k and 2.5k and noticed that when I hold at that rpm (and any rpm higher than 2k) I get a vibration that seems cyclical, aka about a 1.5 second vibration and then nothing and the the vibration...repeat as desired. This occurs regardless of the rpm (as long as it is over 2k rpm). I do know that for years I've always had a "womp womp womp" sound at the end of a 1/4 mile run...any ideas? It literally sounds like a bad wheel barring but I did the "test" in drive and neutral with the same results. The car has bolt ons w/ a FLT stage 4 trans and a vig 3200 stall. any ideas? Again this was in neutral as well as park and i've felt the same type of vibration in 3rd gear going through the traps. Although it may not be related. thanks guys!!

Bizzles

iTrader: (3)

Discussing a bit with my dudes I have two thoughts.

harmonic balancer

-or-

warped flexplate

I'll have to see but I'm pretty sure the cycle of vibration to no vibration doesn't change with the RPM, for example at 2k vs 3k the cycle is the same. Which is weird that a vibration would do that in neutral since it's just the motor spinning.

thoughts??

gmgg09

Finally, someone who sounds like has the exact same problem I do!!! Same cyclical over 2k, same "womp womp womp" on decel from higher rpm (above 3k) even in park except mine just about shakes the mirrors off. Didn't notice it when i bought the car at 80k, but put 20k on it over the last 2 yrs and tried multiple things that have yet to work. From start to now replacements parts in order: flex plate / converter; harmonic balancer; motor mounts; plugs wires; engine (long block, intake, injectors) / trans; water pump; tuned; and I still have the vibration. Next I'm going coil packs and tranny mount even though there's nothing wrong with the current one it may be some type of poly mount which i've heard can cause Harmonic vibrations. If that doesn't take care of it I'll have to say F-it and I'll figure it out when it breaks.

How long have you had the car? How many miles? If the Balancer doesn't fix it, you can pull the starter and stick a dial indicator on the ring gear to see if it's warped. If not I'd suggest disconnecting the converter pushing it back and running the engine which will take it out of the equation. Hope you find yours without going through the headache I've been through, and when you do let me know if it's something i haven't tried.

Good Luck

mannyman84

iTrader: (2)

Double check your torque converter bolts and make sure the are tight. I've seen some get lose.

Bizzles

iTrader: (3)

I've had the car since 2005, about 97k mi. It's certainly weird, haven't had a chance to drive it yet but i'll certainly let you know if I figure out what it is.

Problem is my car is so loud I have no idea if it's a new problem or it's always been there and I just now noticed it lol, I'll have to try out a few more things to see if I can get it to change or move.

GMgg09 what mods do you have? (you can PM me if you don't want to share)