im replaced my 4.8 manifold with one off a escalade. 5.3 i guess. but it wont stay runnin unless i hit on the gas when i start it and then it idles really high up and down and dies shortly after. i dont know if i have the injectors in all the way. im guess thats whats wrong but any advise anyone? and how do i get the injectors to sit in if they arent?

 

well, first question arises....why did you replace the intake....they are all the same, 4.8, 5.3, 6.0. second thing would be to say make sure the intake is torqued down correctly. next is to check the various vacuum lines (pwr brake booster, evap, egr, etc...)

 

why did you replace your intake... damaged? anyway to set the injectors in all the way just put alittle bit of motor oil around the injectors o rings... not alot a little dab will do you.

 

check and make sure you didnt get any wires underneath the intake..hear a wistling sound?

 

yea mine had a hole in it. i didnt see anything caught under it but it does sound like it has a vacuum leak. im pretty sure i checked everything and found no leaks tho. might just be the intake suckin im hearin since its at 4k or so rmp.

 

turned out to be a wire cought under the manifold and a o ring on the crossover tube bad. thanks everyone