Ignition coils are heating up and will not restart until they cool. need wiring diagram for installing an external resister

Disconnect the ignition coil output wire at the distributor cap.
Connect a spark plug to the end of the ignition coil output wire which you just disconnected.
Connect a ground wire to the threaded portion of the spark plug.
Disconnect the ignition coil ground wire from the negative terminal on the coil (Green Wire).
Connect one end of a ground wire to the ignition coil negative terminal.
Turn the ignition switch to the ON position.
Tap the other end of the ignition coil ground wire jumper on an good grounding point (for example the battery negative terminal) and look for sparks at the spark plug that correspond to the frequency of your tapping of the ground wire.
If you have a good spark at the spark plug, the ignition coil is good.
If you don't get a good spark, check for approximately 12 VDC from the coil positive terminal (black wire) to ground with the ignition switch in the ON position. You should also get approximately 12 VDC from the coil negative terminal (Green wire) to ground
Ignition Coil Resistance Check

In addition to the test above, you may elect to perform an ignition coil resistance check as confirmation of the coil's condition.

Check the ignition coil primary coil resistance by connecting an ohmmeter between the positive (Black wire) and negative (Green wire) terminals on the coil. The resistance should be 0.4 to 0.6 ohms.
Check the ignition coil secondary coil resistance by connecting an ohmmeter between the coil output terminal and the ignition coil negative terminal. The resistance should be 5000 to 7200 ohms.

You may have a bad coil or bad ground or wire connection

check that the coil is the correct voltage in use start/ run 12 volts or start 12 volt run 7.5 volts ( a 7.5 volt running on 12 volts= faulty ignition resistance wire == all the time will fail from over heat condition)
next feel the coil when it stops --it should be warm but not hot to the touch
next test/ replace the ignition control module
These items will loose capacity to operate if they get too hot from component failure but in cooling down will again work until they get hot again

We do not have wiring diagrams here at fixya, the manuals are copyrighted material I did find this one picture with numbered wires that may help you hook things up.

Not sure what the question is ?
The heater for the choke and the coil draw alot of amps.
If either component has an internal short to ground, the wire will be very hot rather than just warm.
You could disconnect either component and see if the wire is still hot.

possibly a vacuum leak , or external coil, the coil could be braking down due to heat and age of coil, i have had some that had bad coils and the engine would not want to restart untill cooled down, does' your engine light come on, if so , you need to have a code tester to check for trouble codes that the computer might have picked up if any, hope that this information was helpful.

The coil wire slide on type ( not Bolt on ) have a tendansy to expand if they get to hot, thus causing an open in your ignition system and shutting down your engine. much the same as driving down the highway and sudenly turning off your key.After a period of cool down you turn the key and the motor firers up right away because the coil cap has had a chance to cool down as well and cuntract to its original shape ounce again and is ounce again making proper contact,untill it gets to hot again and then the same thing will happen.Solution replace the coil half cap and wires to it.

Ignition Module REMOVAL & INSTALLATION

1. Turn the ignition key to the OFF position.
2. Separate the wiring harness connections.
3. Unbolt the igniter.
4. Loosen the nut holding the wire lead onto the coil.
5. Tag and disconnect the wire lead.
6. Lift the igniter off its mount.
7. Installation is the reverse of removal.

---

The following is related by not the same as the 'ignition module.':
Ignition Coil TESTING 1994–95 Models

1. Turn the ignition key to the OFF position. Disconnect the negative battery cable. Wait at least 90 seconds from the time the negative battery was disconnected to start work. CAUTION
   Work must be started after 90 seconds from the time that the ignition switch is turned to the LOCK position and the negative battery cable is disconnected from the battery.
   
2. Using a 5mm hexagon wrench, remove the 2 cap nuts and the V-bank cover. Fig. 1: Remove the V-bank cover, a 5mm hexagon wrench will be needed — 1MZ-FE engine
   
   
3. Disconnect the ignition coil wiring from the coil being tested. Fig. 2: Disconnect the ignition coil wiring from the component being tested — 1MZ-FE engine
   
   
4. Insect the primary coil resistance using an ohmmeter. Measure the resistance (cold) between the positive and negative terminals. Resistance should be between 0.54–0.84 ohms. Fig. 3: Attach an ohmmeter to the positive and negative terminals of the coil — 1MZ-FE engine
   
   
5. If the resistance is not within specifications, replace the ignition coil.
6. Reattach the ignition coil wiring.
7. Reinstall the V-bank cover. Push on the cover until a click is felt, then tighten the cap nuts.
8. Connect the negative battery cable. Reset any digital equipment such as radio memory and the clock if necessary.

its quite possibly the crank angle sensor as they do this when they heat up,the car wont start,till it cools down,you can get the resistance checked on it to see if its ok,but you will need someone with experience to do it but its not a hard job

Check the prrimary and secondary resistance on your coil. Also check the resistance of the plug wires and plug gap.

Try your ignition coil. That year model chevy has a dry running coil and it does not go out all at once. It will spark and run while cool but just as soon as the everything starts to heat up the resistance in the coil begins to build and it quits firing. After letting the vehicle set a little while and cool off it will fire off and run just fine untill it starts to heat up again.