I thought id post this here to so i can get more responses . I just bought an 87 Camaro z-28 with a high performance 355 engine and 700r4 trans and i noticed that from takeoff the car shakes and vibrates alot you can feel it while sitting in the seat. and also just sitting in the car while in park and reving he engine the car vibrates. i was told i have to run high octane about 94 or higher but right now im using 91 octane could that be the problem?

 

I get the same thing in my stock GTA, I know the tranny is going and shakes like a bitch sometimes, the seals are going in my 700R, as for sitting in park and shaking mine does it too, so I`m guessing it`s still the tranny, maybe the converter???. I hope anyway, I don`t want to do a engine rebuild too.

 

If it does it while sitting in park, then its something forward of the transmission, like the Tq Converter or Flywheel, or possible even the motor itself.

 

What is your engine combination? Unless you are running 11:1 compression or higher, you shouldnt need to be anywhere near 94 octane. Guys with stock L98s can easily run 87 and be fine. I run 89 with 9.5:1 compression and 8* timing (6* stock).

 

Im not to sure what the engine combination is on my car is but the guy i bought it from said i have to use high octane gas.

 

its worth a shot to check out the motor mounts and trans mount

if they are shot you could be getting all kinds of vibrations

 

ok today i put some 94 octane gas in it and took it for a drive it ran alot smoother and didn't vibrate as much but it still has some vibration but not as bad im gonna try changing the plugs and wires.

 

Definitely look for some kind of misfire, be it bad plugs, plug wires, rotor/cap, really bad valve adjustment, vacuum leak, bad compression, dead injector, etc...

 

if high octane gas helps reduce the problem i would suggest looking for causes of pre-ignition

such as carbon build up in the cylinders, ignition timing off, knock sensors inoperative, etc etc