Hey I am new to this site and need advice on my truck here is the story...

So I did a complete rebuild on my 1996 dodge ram 1500 5.2. Once it was finally done and put it back it in it fired right up no problems but when it warms up the idle fluctuates for a couple minutes then dies it's been about 2 months now I have replaced.......all vacuum lines, my tps, my iac, my map, crankshaft sensor, pick up sensor, water temp sensor, intake manifold air temp sensor, both o2 sensors...it's got the proper fuel pressure and no check engine lights..if you have any ideas at all please let me know thank you.

 

I suspect you still have a vacuum leak, that opens up as the engine warms. Try re-torquing the intake bolts. If that doesn't help, disable PCV system, and see if you have pressure, or vacuum, in the crank case.

 

i was going to guess a vac leak also. try to make sure the intake bolts are torque still and also make sure the throttle body bolts are good and tight. if still does it then take some carb cleaner and shoot it around where gaskets would be and listen for a change in idle, if u do u found the leak. pay particular attention to the rear of the intake manifold. around the dizzy. those gaskets are kinda hard to keep straight sometimes when u sit the intake on.

 

Ok I checked the intake bolts they are torqued right and I tried the pvc valve and it's got a lot of vacuum. ...and I tried to spray around the intake with starting fluid and it never picked up..

 

Disable PCV. Pull the valve out of the hole, and tape off the hole. (or, pull the line from the intake, and plug the port on the intake.) Take off the oil fill cap, and start the engine. Do you have pressure, or vacuum, at the fill hole?

 

There is no pressure or vacuum at the fill hole

 

That's odd. Should be something there..... Plug the fat hose the comes from the air filter box, and the hose to the PCV valve as well, and see if anything changes. You *should* get a little bit of a breeze coming OUT of the oil fill hole.

 

Ok I will do that first thing tomorrow. .what could that mean?

 

If there is a breeze coming out, that's good news.

If there isn't, it means you have an internal vacuum leak..... that means, intake needs to come back off.

 

So it could probably be that little plate that goes on the bottom of the intake?