Cleaned spider intake valve ?I don't like that, there is a tsb on these injector poppets(spider). They stick and some stay open, mostly they stay closed. I seen this as a stalling ,running problem. I am guessing , with out more information that is all we can do. We need to know what we are missing.
I will keep trying for you. Do you have a tilt steering wheel. I have seen steering columns that are very loose cause the ignition switch rod to move enough to shut the car off like turning the key.The ignition system is another place to go. Not uncommon for the Ignition module or crank sensor to shut down from heat when the vehicle has a lot of miles. I have seen many make and model GM's do this. We need to see what is lost when it shuts down. I would go right to a plug wire and pop a screw driver in the end of it, hold it next to ground and get some one to crank the engine. Make sure you are not grounded, or ouch. If you think it's ignition we need to catch it when is doesn't work.
keep trying Mike