Toyota Repair: 1987 Toyota Corolla, toyota corolla, gas tank

Question
Hi Ted,
I have a 1987 Toyota Corolla,1.6L,4 cyl with a carburetor.It did run poorly.It "missed" a lot and seemed hard on gas.I replaced the spark plugs and wires and that improved it greatly.
(I noticed the old spark plug ends were black and sooty.)
However I am still having a couple of problems.
Sometimes especially when I am going uphill the car "cuts out" but does not die.
Also,sometimes after driving it and I shut it off and try to restart it,it won't start.But it always starts after waiting a few minutes.It is unpredictable as to when it will do this;it seems to be doing this randomly.
I bought a bottle of STP carb cleaner and put it in the full gas tank.I don't know yet if it will help.
What could be causing the car to do this?
It is in otherwise good shape to be an older car--it burns no oil and has good power.
Thanks for taking the time to assist me.

Answer
A couple of more things you need to check and maybe replace, the distributor cap and the rotor also check the coil inside the distributor, remove the coil cover and check for cracks, check for burned through spots on the underside of the coil with a mirror and a flashlight, I have seen quite a few of the coils fail this way.