I am pretty sure I want to run my vacuum hose into the back of the intake manifold...unless anyone would let me know of a better place to hook it up. I've got 1/8" diameter hose going to the gauge and I need to order the correct size t fitting but I'm not 100% sure what size is needed. I would rather not cut my stock hose to measure or disconnect it to until I have all of the parts I need to finish the job. Looking at it makes me think a 1/4" or maybe even a 1/2" but I am not positive. What is the diameter of the hose coming out of the intake manifold?

This is on a 2006 MC LT 3.9.

 

most likely the 1/8th is good and any port you can tap in to will be just fine.


i will ask though..... why are you putting a vacuum/boost gauge on your car? unless you have put a turbo or s/c on it, there is absolutely no reason to do so.

 

It is mainly for fuel efficiency purposes to help me learn to drive without burning as much gas. In the last couple of months my mileage per tank has gone down from about 400 miles per tank to about 350 miles per tank and I would like to save the gas as much as I can. The wider tires I put on the car in March is probably contributing to my lower mileage, but 50 miles per tank seems a little much. The tire diameter is pretty close to what I had before. I went from a 225/55-17 to a 235/50-18. I also added a cold air intake right before the new set of wheels and tires. Other than that nothing has changed. Ran some complete fuels system cleaner through it as well. I am not sure if the plugs and wires have ever been changed and it's at 120k miles now so that will be my next job to tackle and hopefully that helps a little bit. Eventually I'll have an intake cleaning service done and a new fuel filter wouldn't hurt either.