Service Vehicle Soon alert with No boost

[YoungBonne12]

i am assuming my intermittent service vehicle soon light comes on because there is an issue with either my actuator or solenoid or vacuum tubing. i checked things out and here's what i observed:
Broken rubber cap on vacuum above actuator, rubber tubing very brittle connected to actuator and to solenoid. assuming T fittings are brittle as well. When i checked out the actuator, here's my summary. lets assume that fully extended, touching s/c base is position 0 and fully hidden in actuator is position 10. during idle, actuator is about at position 2. when gas is given, actuator taps position 0 then retracts to about 5 or 6, then returns back to 2 with idle. is there a problem here? the only thing i can figure is that the cracked, old, worn lines are causing the vacuum to be non sealed. when i found a new rubber cover for the nipple coming from the piece about actuator, i went down the road and had 7-8 pounds of boost, but a 30 min trip went on to show the same problems as before. Any recommendation or help would be greatly appreciated. thanks!

[redzmonte]

i would replace the vac harness's and that will most likely clear up your Evap issue you posted in the other post. GM offers both harnesses for reasonable price and can be swapped in about 20min. thats where i would start

[redzmonte]

* Vac harness from dealer PN: 24508742 (large one from TB around the SC to the SC BBV. ~$30
#5 is the part



* U-bend hose attached to the EVAP Canister Purge Solenoid GM# 24506665 - ~$17
#4 is the part

[YoungBonne12]

We own a salvage yard and have a bonneville ssei and a couple other 3800 s/c. I would just need to know what all I would need to check to replace