Chevrolet Repair: engine, fuel pressure gage, chevy silverado

Question
Hello,i have a 1991 chevy silverado 5.7 liter throttle body 4 speed automatic.Trouble is on cold start ups it has to turn over several more times to start than normal and then when still in park the idle go's up and down-up and down almost to the point the engine stalls.Then when i drive it,it spits and sputters and misses until it warms up then it improves.Also when i shut it off warmed up and wait 15 to 20 minutes then start it it starts fine and idle comes up then engine dies,pumping the gas does not help then it starts hard but once running seems to run fair.Any suggestions would be appreciated.Thank you.

Answer
What first needs to be determined is if the problem is FUEL or IGNITION related and this requires numerous tests with a fuel pressure gage and a scanner to determine which way we need to proceed.

There are just so many possibilities as to what it could be that without knowing if it is FUEL or IGNITION related is impossible to make a proper diagnosis.