I have another post about dist wires, but here's another question: When the engine was running (before my bro-in-law sold it to me) there was a knocking sound coming from the valve cover area. My brother swears its a rod, but the noise is definitely up high. Does anyone familiar with Supras know what I might check before resorting to yanking the engine and checking the bottom end?? Thanks again.

Is it a light tapping sound? = valve adjust......
Piston slapping the walls ???

Rod knocks, (bearings) sometimes can be made to sound up by lightly playing with the throttle. Barely increase and decrease the rpm a little bit, if it gives a rattle sound, it could be a rod bearing. Pull spark plug wires, one at a time, and ground them. If the sound stops on a certain cylinder, its that one bad.

It doesnt sound like piston slap. We did pull a plug wire (before the wire chopping) and found the source. The fact that the noise goes away then is the reason my brother thinks its a rod. Im unconvinced. The sound is up high. I put my ear next to the valve cover (drivers side) and can distinctly hear it there. Nowhere else. Does anyone have any guidance on adjusting valves on these cars? I didnt know lash could be adjusted on them. Im trying to avoid buying a manual until I know whether to keep it or not. Call me cheap....Anyway, thanks.

there are manuals online

http://www.cygnusx1.net/supra/library/TSRM/index.html

Does it make the noise constantly no matter what, if it doesn't do it all the time, does it do it under load, when your actually driving the car. Does it do it if you just raise the rpms up from under the hood?

The knock is always present. At idle and revving. It does go away when the plug wire is removed and only then. It did quit briefly when the previous owner had it for about 2 minutes when he started it, but came back. Thanks.