really? i didn't think weight on the bushing would matter at all....

 

I may have misunderstood what bolt is missing. I thought it was one of the drive shaft bolts on the flange, where the isolator pads are. My mistake...

 

i'm thinking about just getting a strong grade bolt and nut that is close to the stock ones since the lexus dealer is about one hour away.

 

Update:
i got the vibration fixed, it was b/c of the missing bolt on the drive shaft bushing. i just happened to have a bolt in my bolt bucket that was about the same size and length. went for a test drive up and almost no more vibration...but here's the thing, when i got back home, i parked it and turn the car off, checked out everything making sure it's all good turn the car back on to go for another test drive but right when i was going down the road it felt like it doesn't want to go any faster. i'll give it almost WOT and it barely moves. from a stand still if i give it gas the rpm's will go up to 1500 than the car starts to move, sounds to me like the transmission is going out (the previous owner just got the transmission rebuilt two years ago).

so i drove it back home and parked it and popped the hood open and smokes starts to come out, i looked under and it seems like it has an exhaust leak from the headers to the exhaust. try revving it but it feels like it doesn't want to and will drop down to 300 rpms once i let off. maybe it needs a good tune up? this car has been nothing but trouble since my brother got it two weeks ago and i'm trying to avoid having to get a new engine for it....

 

did they ever put a transmission in it ? the po or did they mess with it for any reason? post a pic of the drive shaft on both sides where the bolts are, mine did the same thing when i was dumb and put my driveshaft on the wrong way..... be fine under 35 and then shake violently after that

 

sorry see that you got that fixed.... i know clogged cats will do that under load

 

I had terrible vibration after a transmission rebuild. Vibration was worst at about 1300 and 2000 RPM whether driving or sitting in the driveway. Tires were replaced...no difference. Several garages, including a Toyota dealer, could not pinpoint the problem. Finally, a Lexus specialist said it was the engine mounts and transmission mount. They were replaced and it is again smooth running! The vibration was terrible at about 2000 RPM which is about 65 mph on highway. I am disappointed that the engine has so much vibration to be dampened by the mounts...but happy that the mounts are up to the challenge.