Can anyone help with vacuum system for this truck.following. Somewhere in the system there is a leak. I can not for the life of me find a diagram of the vacuum system for this truck. Does anyone have one?

Also, when I perform the smoke test, where exactly should I insert the smoke?

Thank you

 

Should be a diagram on the rad support, they are hard to read some times but its there.

There shouldn't be too many vacuum lines

Main ones are for power brake booster and PCV valve
PCV Valve is on the drivers side, down low just above oil pan, best way to see it and get at it is thru the drivers side wheel well

In 2003 you also have IMRC(intake manifold runner control) and it used vacuum, IMRC valve is just to the rear of PCV Valve, the hoses often cracked

Then there is:
a vacuum hose to the EVAP Purge valve
To the EGR solenoid valve
To the Vacuum reservoir

 

Brake booster
PCV
IMRC (under runner 3)
Brake Switch Vacuum Feed
Fuel Rail Pulse Dampener
HVAC - A/C heater bypass
HVAC Vacuum reservoir

When I took my truck apart, I found all the stock vac lines to the IMRC and to the pulse dampener to be split/broken. The IMRC valve tends to just fall apart with age as well.
The pulse dampener is a bit of a pain to get at when assembled, but some careful maneuvering with smaller hands can easily slip on some vac hose. Its feed port is on runner #1
IMRC feed port is between runner 2 and 3, on the back side near the solenoid. Both vac ports are "shrouded" with a half circle shield molded into the intake. From the Manifold the vac should go to the side port on the IMRC control, and the bottom port should go to the IMRC valve.

I melted the vac line to the reservoir some time ago, and only got defrost. That line runs from the back of the intake manifold to the passenger wheel well to a globe, which has two ports. One to the manifold, and one to HVAC. Its to prevent the dash vents from switching to defrost every time you accelerate.