I just recently purchased a 1992 LS 400 with only 93,000 miles on it. A few days after I brought it home, I noticed that the car sporadically shudders when I am at a stop light for a minute or so. When I shift it into neutral, it stops. It seems to do it whether the A/C is on or off. I'm thinking bad motor mounts, but this I've never owned a Lexus or a V8 that is this old. I know that this car sat pretty regularly for the past 1-2 years, so it could be working some kinks out. I'm asking you experts out there, has anyone experienced this or does anyone know what it might be?
UPDATE: Ok, I noticed that when the engine shudders the RPMs drop by a couple hundred. It still only does it when I have the brake applied while in drive. Any ideas? Your help is much appreciated.