need help don't know what else to try

i have a  92 jimmy 4.3 vortec   went to work  and started running rough when i got to work came home still running rough    replaced     spark plugs ,wires , cap, buttons, o2 sensor,  both trottle relays , water sensor ,fpr sensor ,fuel filter,  map sensor,tps  fuel pump getting 62 psi  at the engine  sparks plugs getting  blue spark, took off the cat and put a new muffler on starts  sounds like its missing  rough idle still  checked to egr valve thats fine  put a code reader on and says things r fine passenger side manifold is warm the driver side manifold is hot replaced those things one at a time when one thing didn't work tried something else vacuum is  about 5     need help please

5 pounds of vaccum does not sound right for these engines. What is your compression in  all cylinders? You could have a bad air leak in your intake manifold, maybe replace your intake manifold gasket, uper, and lower. If your compression is low id check  for blown head  gasket. Five psi. of vaccum is way low. Any check engine codes?

took the plemon off again and this time found gas in the inside  i was told thats not good so i got the fuel injector going to see how that works today if its still missing we'll check the manifold and the vacuum again  code that come up 12 and thats normal but u can hear its not normal

Did you ever find out what the problem was?  

replaced the spider with a new one  still had problems got tried of it and took it to a garage they said the spider was bad took it back got a new one    blown out the return line with air  still not right something still not there

find the problem  broken valve spring

Yikes!  That would do it though!  Thanks for the followup!!