Vacuum Leak?

[RonB]

I was driving (94' EB) the other night and when I stopped at the light I noticed that when idling, the engine was bucking. I also heard a hissing sound. When I got home I opened the hood and traced the problem to a hose not being connected on the Vacuum intake above the PCV valve (V6 Pushrod Engine). There are 6 hose connections going into the intake and all but one was connected. Here's the problem. I could not find a hose that plugs into the one open line. I looked everywhere for the missing hose. Should one have a dummy plug on it? I looked in the manual (Haynes) but it doesn't meantion where they connect. I put some electrical tape over the one input line and the Idle is now fine. If someone can email me a drawing of where the hoses connect I would really be appreciate it. I checked the whole engine compartment and I am at a loss.

My Email is arby500@aol.com

Thanks.

 

[slow-demon]

The cause of all the missing vacuum hoses is probably a leaking auto transmission vacuum modulator. The modulator's diagpragm is leaking and transmission oil is being sucked into the engine. All the transmission oil is swelling up all the vacuum hoses and plugs. About the vacuum tee, one vacuum hose is connected to the brake booster, one is connected to a hose which is connected to a hard metal line that is bolted to the upper intake manifold. That line leads to the transmission. Now below the vacuum tee is three hard plactic lines that may still have the rubber ends which connect to the tee. One of the lines leads to the interior accesories, such as the blend doors for the a/c. The other line leads to the fuel pressure regulator. The other line leaks to the EGR valve solenoid. If the rubber ends are not on than you can either buy some ends or use rubber hoses. Also check the rubber end that connects to the fuel pressure regulator.Chances are that the rubber end is swelling up also. The fuel pressure regulator is located towards the front of the engine, behind the alternator. Another vacuum hose leads to the speed control servo which is located on the driver side fender apron. What should be left is one extra vacuum line from the tee that should be plugged with a rubber cap. You should also replace the vacuum modulator. Also on the radiator core support is a vacuum diagram that shows the vacuum routing. I also recommend replacing your spark plugs because the may have gotten slightly fouled from burning the ATF in the combustion chamber.


[This message has been edited by slow-demon (edited 10-19-1999).]