94 Accord LX recently began making a knocking sound when cold
 

Looking for some help. My car recently began making a knocking/clicking noise when I start it up in the morning or after being parked for a few hours with a low grumbling idle. Never sounded like that before. The knocking/clicking noise is worse when I give it gas during hard acceleration. Not so bad on easy acceleration. After the engine warms up, the sound goes away. Sound kind of reminds of a tractor or diesel engine.

I also noticed too that when I'm stopped at a red light, the car begins to vibrate. Not excessively, but way more than it used to. Checked the motor mounts and those seem to be fine. When the vibrating started, I checked the oil and was about 1.5 qts low. After adding oil, vibration eased but then returned a few days later.

Are these issues (vibration and clicking sound) related and how can begin to troubleshoot and ultimately fix it?

Car details:
94 Accord LX coupe
Automatic
185k

Any help would be greatly appreciated!!

Best thing would be to pinpoint the location of the sound. It might be the beginning of an exhaust leak?

Valve noise is another possibility, but that shouldn't change much with acceleration.

Did you check particularly the rear engine mount? It's vacuum-operated and supposed to go soft when idling in Drive or Reverse. You can unplug the solenoid valve while someone is holding the brake, idling in D or R. Make sure you trust the person holding the brake...