I just picked up an '87 rcsb with a 305 TBI. Once it warms up it does not want to stay running. It will run fine, no miss or anything for a few mintues until it warms up, then shut off. I have just replaced the infamous ignition control module and it did not really help anything. I think it has to be a sensor or module. I've also heard that the ecm in these early fuel injected trucks can heat up and cause the same problem but I think i've cut that out of the mix, It does not heat up at all. One thing I did notice is that the coolant temp gauge is not working, the sensor on the cylinder head has a "hook" type connector on it, it is actually not connected at all and the sensor itself looks stock. Could the coolant temp sensor cause this problem?

 

ok so I am not thinking it is the coolant switch. I am leaning towards fuel pump, ignition pick-up coil, or possibly a bad injector. The truck runs ok, maybe a slight loss of power and it seems to shut off only after warming up. It always starts right back up and runs for 10 seconds or so, then stumbles and shuts off. I am going to test some things this weekend and hopefully find out but has anyone else had this happen to them?