GM-GMC: 91 Chevrolet Sonoma SLE, egr valve, fuel pressure

Question
Truck is fuel injected.  The symptoms are such that in warmer temperatures while driving, the truck will simply stall.  Does this at ide, at sppeds of 20,30,50.....always starts back up relatively quickly.  Battery is holding a charge.  Fuel injectors are spraying fuel.  Ditributor cap was replaced, along with wires and plugs.  Same result.  Any suggestions?

Answer
There are two things that you should check.  The first is the EGR valve.  If it is sticking open, it will cause a rough or a stalling condition.  You can remove the egr valve and check for carbon or debris sticking the pintle valve open.  The second is your fuel pressure.  If the fuel pump is failing, it too could cause the concern you are talking about.  Install a fuel pressure gauage and try to check or observe the pressure when the engine dies.  If the pressure falls before the engine stalls, it is likely a fuel problem.
Hope this helps