dammit i keep forgetting that supraforums can't register any new members at the moment
i would replace your ignition module (ignitor) and see how you get on...
your local junkyard should have one, just ring around and see if you get one
87supraguy... good guess but this model supra doesn't use a rotor and cap as such... it uses a cam position sensor which at the end of the day does the same thing just more electronically fancy lol
but you did remind me of one thing to check with that....
Supraman... have a look at the plug on your cps... look at the wires... if they look dodgy or anything i would rewire the plug... the cps has been known to cause strange problems in the past
good luck