OK folks so I have an 86 with the 2.8 5spd. It runs fantastic no problems there, but the car does vibrate/shake quite a bit. This is definitely related to the motor not the suspension or trans/rear end, because it does it while stationary in neutral. Its not really so bad until I hit 3000rpms when there is a marked increase in the vibrations, actually becoming more smooth after 3800rpms or so. Also, at low idle (700 or so) it will get a little shakey.

So, I blipped the throttle with the hood up, the motor didn't really lurch very much. Nevertheless, I put in new stock motor mounts, transmission mount, harmonic balancer, all shocks/struts, and gave a tune up (plugs, cap, rotor, wires). Now, this has helped a lot (when I first go the car it was much worse) but I can't seem to iron out the aforementioned vibration. I remember I had a 87 camaro 15 years ago that wasn't nearly this rattly.

The passenger door does have the classic wear on the hinge, when I open it there is a dead spot where the door clunks down a little bit, however I can still close the door with ease with one hand and the striker holds it tight. Passenger door operates as it should. I do have the kit and spring compressor to repair that hinge, just waiting on a couple strong friends to have a day to help me with removal and reinstall of the door. However, with the door closed it locks tight, and I have a hard time imagining that it is rattling significantly.

Any suggestions on where I should go from here?

Thank you

 

is the engine misfiring at all , since u did everything on the front of the motor i would investigate the clutch and flywheel

 

No misfiring noted, no CEL, clutch seems to work fine without any vibration felt in the pedal. Could you be more specific on what to look for in the flywheel?

 

Had a very similar issue. Turns out the previous owner replaced my harmonic balancer and had no idea it used a woodruff key lolfail

Was a good excuse to do the front main seal I guess haha