1990 RS (5.0 TBI) -- Whenever I pull up to a stop light in first gear, with the clutch depressed (disengaged), she will begin to shake violently and knocking a sound is emitted. It almost sounds like the exhaust is shaking back and forth. Sometimes are worse than others, and sometimes she'll start out with a small shake then grow in to a more violent one. However, with the clutch still depressed, I'll take the car out of gear, and the shaking will stop. Let me reiterate, she'll ONLY shake when in gear with the clutch depressed. At idle with the trans out of gear, everything is normal, no shaking. Often times, when I rev the engine a little, the shaking and knocking subsides.

This may, also, be relevant, she has a problem shifting into 1st and Reverse. I get a harsh grind if I don't shift into 2nd then 1st, or 5th into Reverse. I have a couple idea's of what may be causing the problem; Clutch drag, bad synchros, motor mounts, etc. But I'd like to hear from you guys and see if you've had a similar problem and could shed some much needed light on this unfortunate subject.

It would really be nice to figure out what's causing this and fix this ear sore, so I don't looking like a total ***-jack with a beater Camaro:/

 

Well if she were mine I would get the rear safely up off the ground. Resting on jack stands and block the front tires. Get some help and you could lay off to the side and let a buddy try and duplicate the shacking while you watch. Maybe could see the problem then.