Timing problem
 

Hi,
My 87 NA Supra has been sluggish for awhile now so I checked the timing and it looks like the ECU is not adjusting the timing automatically. I loosened the bolt and moved the distributor both ways and the rpm increased and decreased without shorting out the diagnostic plug. Anyone run into this problem before?, and if so what fixed it?

Probably works fine
 

You won't necessarily 'see' the timing move (looking at a timing light) while you rev the engine sitting there in neutral.

The computer looks at RPM, vehicle speed, load, throttle postion, engine temp., intake air temp, etc, etc,etc. Then it decides where to set the timing.

Just jump the terminals, set the timing to 10*-15*, remove the jumper, and drive it. I bet the timing is working correctly, as I have not seen one thread on several supra forums about timing not advancing properly.
(nor in the shop either).

open circuit
 

I found an old copy from a toyota repair manual I had the toyota dealer here
burn for me that has the plugs for the ECU and read the wires for the distributor to the ECU and found an open circuit, further troubleshooting revealed the problem to be in the distributer itself. I am picking up a used one tomorrow and will install it and see if the problem is fixed.