Here is what we are working with....



First off, whats this thingy?



Its got a port for a vaccum line in, and out.

Where do both ports connect to?

Next, whats this plug?



I cant find anything obvious un-plugged, so Im confused.

This vacuum port is on the back of the intake manifold,



And this one is ontop of the intake manifold



Any ideas?

Also got an vaccum line that comes up from what looks like the transmission area, and pops up between the 2 fuel lines on the lower intake

 

#1 is the EVAP Purge solenoid. The open port runs to the EVAP canister which I believe should be somewhere under the hood for the 1st gens.

#2 looks like it might be what goes onto the high pressure switch on the back of the A/C compressor. See if it can reach over there. It might just be routed incorrectly.

#3 is the vacuum port that connects supplies vacuum to the HVAC & 4wd (if equiped). It will run from the intake to a check valve, then branch off to the reservoir (vacuum ball), HVAC, & 4wd (again, if equiped).

#4 - I believe this is for the EGR valve and would run to the EGR vacuum solenoid.

And about the line that is near the dipstick, this could be the line that should connect to the vacuum source at the back of the intake, just fallen down and caught in the lines. Or it is possible that it is the vent for the transfer case (if 4wd).

 

I found where the plug goes, it was to the coolant temp sensor wayy under the EGR valve and a PITA to get it, probally why I missed it the first time.

Im going to keep looking for this EGR canister, alldata isnt providing much help other than this:



On that note, I dont ever remember pulling any vaccum lines going to the AC system?

The line I am talking about isnt near the dipstick, its back behind the intake manifold, sticking up between the fuel lines that go into the lower intake manifold.

 

I couldn't recall when they changed from the one under the hood to the one behind the driver side rear tire. If that picture applies to your truck, then that is located behind the rear tire. That is the EVAP canister, not EGR canister.

I misspoke when I said dipstick. I meant lines like you described. So that line you described ran from the back of the intake manifold and was just laying down behind the motor? If it connected to the port near the distributor, then it should have run over to the check valve which should be located near the brake booster. From there, it will branch off to the reservoir (vacuum ball), into the firewall for the HVAC, and down to the transfer case (if 4wd).