Chevrolet Repair: 91 Blazer, vacuum leaks, rich mixture

Question
91 S-10 Blazer appx 180k 4.3 auto 4x4 . The truck will not take any fuel when trying to accelerate. I originally found 2 trouble codes , bad map sensor and bad tps. I changed both items and the ox sensor. Now engine will start fine but after about 10 to 15 secs. as the engine settles down it will try to stall and the injectors load up and the idle rises again then tries to stall and repeats sometimes stalls. Put into gear and stalls unless kept running with accelerator, still will not take gas.  Not throwing any codes but hooked up to scanner I did get a rich mixture reading. I've also checked EGR ok, vacuum leaks  ok, timing ok, even removed the injectors and cleaned. All no help. This is a TBI engine. What have I missed? I had it sujested to me that the injectors were bad, but at $70. a throw I'd like to be sure. Any help would be greatly appreciated.  

Answer
Hi Michael,
I doubt both injectors went bad at the same time.
You should be able to look in and see them spray a cone of gas.
Are you sure there isn't water in the gas?
I wouldn't think water in the gas would cause a rich reading, but it could.
I would check that, and then connect a fuel pressure tester to see what it is holding. Needs to be about 13 PSI while running.
I have had the little hose inside the tank where the fuel pump connects to the line, split, and spray fuel inside the tank, rather than hold pressure on the injectors. The pressure regulator could also be bad, causing the wrong pressure.

Then there is the possibility of the catalytic converter being melted and plugged. You could just disconnect it to see how it runs.

Van