I have a 89' chevy silverado z71, w/ a 5.7 ltr. , w/ 204,000 miles on it. I'm getting spark, timing is correct, getting fuel also but it doesn't seem to be enough. the carb has overhead injectors, I can watch gas come out but the motor won't start. I can spray starting fluid or dump gas in and the motor starts right up but dies when it's gone. I have replaced the fuel filter, and fuel pressure regulater, diaphram, spring etc. , I have also completely cleaned the throttle body and regulator; the only thing I haven't done is take the injectors apart, but I highly doubt they both clogged up simutaniously. Would the "ECM" have anything to do with this? I have also considered the pump, but it does kick on and like I said, it is getting some gas. I refuse to get rid of this truck, It's the best truck I've owned and I've had alot, even as new as a  99' Ram, so I really need to get this figured out. Thanks for your time.