strange vibrations

[karpetcm]

Well this has been happening since ive had the car from day one, at idle it will make this wierd vibration only way to describe it in typing would be Vroom vroom like a generater and its not consistant and the lenght at which it lasts is not consistant either sometimes it will be for a split second and then 2 seconds but its not steady. I can easily feel it through the shifter knob and when i popped the hood and put my hand on the intake manifold i felt it through there as well like its a vibration from the engine. The motor runs strong and extremely smooth no issues at all other then it will make a weird vibration under idle, its not the fans nor has it to do with the a/c it happens when the car is cold or hot. The engine also doesnt make any wierd ticking noises either other then whats normal, so im a bit confused as to what it might be. Only guess i would have is motor mounts but could be way off on that one

[Hi-Po]

How many miles? check tranny mounts, motor mounts.

[karpetcm]

it has 67000 miles on it, i think tranny or motor mounts could be a possibility, usually when a tranny mount is bad and when you hit the gas the shifter knob raises up to much and goes down meaning the mount is too soft, could be the motor but id have to check both to make sure.

[Hi-Po]

Easy to check for sure, ide start there.

[karpetcm]

i just thought about it usually if its motor mounts they vibrate at a certain rpm alot more, not sure about that either but i was told once a while ago thats one of the ways of knowing its a motor mount but then again could be wrong in that as well.

[RaSScal]

Sounds like a tranny mount, notorious for "ripping" on Gen 4 F-bodies. If you replace the tranny mount with a poly mount (versus rubber) you will feel a fair amount of vibration, especially in a manual.

[mark21742]

just a guess, how about exhaust or converter heat sheilds vibrating. I've had to retack weld lots of sheilds that came loose in the past

[PFM]

Only at idle. Does it go away a few minutes after you crank it? Could be the air pump.

[karpetcm]

na doesnt go away, even after driving for 30 minutes it will do the same. It doesnt sound like metal vibrations. Its only at idle, what makes it worse atleast for me is the car drives perfectly fine and as soon as i come to idle it will vibrate but rpms dont drop they stay steady, oil pressure is right at or above 40 the only thing ive observed is the motor does shake going side to side as it does this. When i put my hand on the intake manifold there is no metal or weird noises coming from the motor just that vibration, seems to me motor mounts could be the cause because since the tranny is paired up to it, it also vibrates my shifter handle which also rocks a bit right to left.