5.9 gas common vacuum leaks?

[lifted4x4ranger]

I have a 95 dodge ram 2500 4x4 and I believe I have a vacuum leak somewhere I hear a sucking when I accelerate, also smell gas for about a second when I shut it down, but i don't think its related, anywho, Is there a place that has a diagram for the vacuum lines or are there any vacuum lines that commonly need to be checked? Im getting about 8 mpg driving like a grandpa, motor only has 80k.

[Dodge4x4Texan]

I had a vacuum leak on my 98 on the front differential. It was the reason I had a noise when I accelerated also. Since being your truck is a 95 id say you might just have some old cracked vacuum lines that need to be replaced. You might want to also check your pcv valve on your valve cover I believe, someone correct me if im wrong on that position.

[lifted4x4ranger]

(09-20-2010 09:41 AM)Dodge4x4Texan Wrote:  I had a vacuum leak on my 98 on the front differential. It was the reason I had a noise when I accelerated also. Since being your truck is a 95 id say you might just have some old cracked vacuum lines that need to be replaced. You might want to also check your pcv valve on your valve cover I believe, someone correct me if im wrong on that position.

Yea i know for a fact my vacuum pump for my 4wd is not working so maybe thats it. But i dont think that would pull my gas mileage down would it?

[Dodge4x4Texan]

I couldnt tell you for sure if it does effect mileage or not but personally I would think it does effect it and wouldnt put it pass me. Id start there and fix the vacuum problem that you know you have and see if there is any changes. At least you have a starting point.

[Tango]

The old school way was to spray some quick short squirts of eather, and if the engine reved up a little, then that was the area where the leak was.

[swirvin21]

Tango is right, you can do it with carb cleaner as well, anything flammable

[jeffktec]

took me a while to find the leak in the 4x4 front dif. it was up by the back of the engine, on top of the trans, it looked more melted than cracked, the vacum comes off the back of the intake on the pass side, then goes down the back and over the trans. I tied a string to the line and worked and pulled it out, then fed the new line back by pulling the string- if I did not have a buddy at the dodge parts dept I would have just ripped the old out and replaced it with generic hose and routed it in a easier way.

[Shadow14]

On the passengers side of the intake manifold almost in the center/front to back is you check valve. this is the source of vacuum for the heater and 4 wheel engagement. You could easily unplug this line and put a piece of blocked tubing or a little rubber nipple over it and see for yourself how the truck runs without a vacuum leak/
You can also lay under the truck and check the vacuum lines, there are really not that many of them. I had one blow off when pressure washing the undercarriage.
Also under the dash running your heater are a number of lines.
The kick pad under the steering wheel comes off with 5 screws and exposes a number of these lines.

If you heater works in all settings you don't have a vacuum leak.
When I had a leak I could get my dash vents to work. Only the defrosters work since they are the default setting.

[k3yston3]

I've got a vaccuum leak in my dash somewhere. Under acceleration, the vent will switch to the defrost setting and then flip back after you get offo f the throttle. I have jsut been too damn busy all summer to tear into it and fix it.

[lifted4x4ranger]

noticed yesterday that if I rev the motor with it in Nuetral or Park I do not get the sucking noise