looks like your missing check valve going from the T going into the line that goes into firewall. I have one there and one right off the elbow coming off the intake. But maybe thats right for a 96. HeyYou says he only has one and he has a 96.

 

someone else with a 96 if you could take a look and see if you have one there id appreciate it. i know HeyYou said his is a 96 and does not have two check valves, just the one by the manifold. anyways after replacing the one i still have wild vents, just not as bad. used to just accelerating would make it go to the defrost vents now its only past 40-45 which is better but not right still. next the girlfriend is going to get a new pcv valve and try that. the trucks in houston though and im in el paso. girlfriend has it and shes been working on it pretty good, changed the valve, cleaned the throttle body, put a new cap and points on it, and a few other things. next does anyone know the part number for the door lock actuator? all the wires are melted into it she said and itll need a new one. any suggestions on track bars other than the bd diesel one? with the lift the stock one just isnt cutting it. we replaced the bushing but the other joint is still bad and the bushings already getting a little bit of play in it. thanks for the help!

 

You can download factory parts manual in the FAQ/DIY section.

Also, a check valve can be added even if it did not have one originally and have no side effects.....as long as it is installed in the proper orientation....

 

ya talked to the girlfriend and forgot she picked up a haynes manual so shes already one step ahead of me in getting the pcv valve and door lock actuator

 

Thoughtful girlfriend!

 

so replaced the pcv valve, was working fine. she checked it in the driveway and said it was good. drove to her college today and they started going to defrost again. ill be in houston this weekend so im gonna take a crack at it. i have pics of all the places i need to check and going to install the other check valve she bought into the t connector by the firewall to see if it helps since there wasnt one there before. cant test the cruise control until we hit the junkyard. its missing all the buttons :/ when we bought it i checked the 4wd and seemed fine, gonna do some more tests when im there. good thread, idk how many times ive reread it lol

 

I went to Houston last week...and had the wild vents pulling a load uphill, with gauge showing 4 in Hg and less when vents changed. Local parts stores did not have check valve so I'll have to order. But I am thinking 5 in is pretty low. I was towing a car, but that should not be enough to pull it down. (Not in OD) engine did not lug down, just vac seemed pretty low.

Way too humid in Houston this time of year!

 

ya id start out with the check valves then move onto the pcv valve. altogether $15 and helped the most so far

 

The only place I could find the right check valves was at the dealership.

 

Dealership here could not even find the part in parts manual.......and I have not had a chance to look for the number myself yet.