After engine warms up, at crusing speeds, it stalls as if the ignition is cutting out or the fuel pump is failing. I can turn the ignition off while still rolling, turn it back on and the problem go

P0500 Code: Vehicle Speed Sensor 'A' Malfunction [Location] (axlewise.com)

SYMPTOM 1: ROUGH IDLE IN THE COLD

The engine will not idle smoothly, or it stalls during idle when the engine is cold. When the engine is cold and you take your foot off the gas pedal, the engine runs very rough and may even stall. When you run the engine at higher speeds, it seems to run fine, or at least it runs more smoothly.
Possible causes:

1. If you have a carburetor, you may have a bad accelerator pump or power circuit.
   The Fix: Replace accelerator pump or replace the carburetor.
2. There may be a vacuum leak.
   The Fix: Check and replace the vacuum lines as required.
3. There may be some type of ignition problem.
   The Fix: Check and replace the distributor cap, rotor, ignition wires, and spark plugs.
4. The ignition timing may be set wrong.
   The Fix: Adjust the ignition timing.
5. There may be a fault in the computerized engine control system.
   The Fix: Check engine control systems with a scan tool. Test the circuits and repair or replace components as required.

1. The EGR valve may be bad.
   The Fix: Replace the EGR valve.
2. The engine may have mechanical problems.
   The Fix: Check the compression to determine the engine's condition.
3. Idle speed is set incorrectly.
   The Fix: Set idle speed to the car's original settings.
4. The fuel injectors may be dirty.
   The Fix: Clean or replace the fuel injectors.

SYMPTOM 2: ROUGH IDLE WITH WARM ENGINE

The engine will not idle smoothly, or it stalls during idle when the engine is warm. When the engine is warm or hot and you take your foot off the gas pedal, the engine runs very rough and may even stall. When you run the engine at higher speeds, it seems to run fine.
Possible causes:

1. If you have a carburetor, you may have a bad accelerator pump or power circuit.
   The Fix: Replace accelerator pump or replace the carburetor.
2. There may be a vacuum leak.
   The Fix: Check and replace vacuum lines as required.
3. The fuel pressure regulator may be operating at too low a pressure.
   The Fix: Check the fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. (This is not really a do-it-yourself kind of job.)
4. Idle speed set incorrectly.
   The Fix: Set idle speed to specs.
5. There may be some type of ignition problem.
   The Fix: Check and replace distributor cap, rotor, ignition wires and spark plugs.
6. There may be a fault in the computerized engine control system.
   The Fix: Check engine control systems with a scan tool. Test circuits and repair or replace components as required. (This is not really a do-it-yourself kind of job.)
7. The EGR valve may be bad.
   The Fix: Replace EGR valve.

1. The engine may have mechanical problems.
   The Fix: Check compression to determine engine condition.
2. The fuel injectors may be dirty.
   The Fix: Clean or replace fuel injectors.

SYMPTOM 3: FAST IDLING

The engine idles too fast. After the engine has run long enough to become warm, the idle speed does not come down to normal. You really notice it when you come to a stop and must have to push ******* the brake pedal to keep the car from moving.
Possible causes:

1. If you have a carburetor, you may have a bad accelerator pump or power circuit.
   The Fix: Replace the accelerator pump or replace the carburetor.
2. The engine may be overheating.
   The Fix: Check and repair the cooling system.
3. The fuel pressure regulator may be operating at too low a pressure.
   The Fix: Check fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. (This is not really a do-it-yourself kind of job.)

1. The ignition timing may be set wrong.
   The Fix: Adjust the ignition timing.
2. There may be some type of ignition problem.
   The Fix: Check and replace the distributor cap, rotor, ignition wires and spark plugs.
3. There may be a fault in the computerized engine control system.
   The Fix: Check the engine control systems with a scan tool. Test the circuits and repair or replace the components as required.
4. There may be a vacuum leak.
   The Fix: Check and replace vacuum lines as required.
5. You have a bad idle speed control unit.
   The Fix: Replace the idle speed control unit.
6. The alternator may not be working properly.
   The Fix: Replace the alternator.

SYMPTOM 4: STALLING UPON STOPPING

Car stalls when stopped quickly. You are driving along and everything is just fine ... until you let off the gas pedal and apply the brakes. The engine starts shaking and may even stall. Not a good thing to happen because you lose power steering when the engine dies and could risk an accident.
Possible causes:

1. There may be a serious vacuum leak.
   The Fix: Check and replace the vacuum lines as required.
2. There may be a fault in the computerized engine control system.
   The Fix: Check the engine control systems with a scan tool. Test the circuits and repair or replace the components as required. (This is not really a do-it-yourself kind of job.)
3. Broken linkage.
   The Fix: Repair or replace the linkage as required.

Idling issues can be very frustrating, but with some patient troubleshooting, you'll have a real chance at figuring it out. Remember to always check your engine idle with the air conditioning and defroster turned off, as both of these systems are designed to change the idle when they are on due to the air conditioning system's demands on the engine.

This sounds like the fuel pump is failing. It will need to be analyzed and tested to be sure. the stalling at highway speed could be fuel starvation and the no start when warm is vapor lock, both point to a fuel pump that is not producing at speck pressure.

It may be gas or ignition related. Try to determine which, when it stalls and won't start. With key on, you should hear the fuel pump turn on for about 2 seconds to pressurize the lines and fuel rail on the engine. If you don't hear the pump, and have no pressure in the fuel rail with key on, it is probably a bad pump.
If the pump is working, check for a strong blue spark on a spark plug wire after it stalls. If no spark on any of the plug wires, suspect the crankshaft position sensor or the ignition control module. Either one can cause those symptoms- failing after it gets warm or hot.

I had the exact problem with my 1993 chevy c1500. I found that the IAC was sticking so the engine would die at idle after warming up and the ignition module was pulsing the ECM intermittently after the engine warmed up so the fuel pump wasn't being turned on after the engine died....I replaced the ignition module and the IAC valve and all is good. I don't know if testing the ignition module reveals that it isn't sending pulses to the ECM.

Possible that the fault can be with the fuel pump as the fuel pressure drops off when the pump is hot. In this case you need to measure the fuel pressure when the enigne is running after a cold start and then after it gets warm. Also the same applies to the ignition unit in case the spark decreases or fails when the coil or the ignition system is warm.You can test this with the plug removed and cranked to look for spark.

Could be the distributor or the coil by the sounds of it - coils can be effected by heat and fail

You need to get the trouble codes. The engine light is telling you that. There must be a stored code or two. See what they are and go from there. If no codes are present, have the fuel pressure checked for possible pump failure.
If fuel pressure is correct (check specs, but probably about 45 psi) , then maybe an engine sensor is bad-maybe the MAF sensor. That's just a guess, though. Could be a bad computer, since it stalls at cruising, but could also be a problem in the ignition circuit-like the crank sensor or cam sensor.

Check your fuel pump pressure after it dies, could be a fuel pump. Try hitting the gas tank sometimes it will make the pump start to work again. The fuel pumps are cooled by the fuel in the tank if you run your tank low alot it will overheat the pump and cause the pump to fail.

try removing battery and cleaning all the ground under the battery tray and check main ground wire from battery to engine