Low vacuum pressure

[codex]

What are the causes of low vacuum pressure on these cars? On cold startup I have about 15 in hg and after warm up about 17.5 in hg. Everything I read says a normal engine should have at least 20 in hg. Does this indicate worn valve seals or piston rings? I've looked over the vacuum lines and do not see any place for there to be a leak, could a very small vacuum leak cause a reading this bad? Is there any way to test the gauge?

 

[orng1]

It could indicate that your due for an oil change or the car is in need of some type of service. It's not running as best as possible. Maybe the EGR is sticking open or something else may be causing it. I get that from my car sitting for long periods of time. I've gotten down to almost 0 vac. After the car warms up and I drive it for a good while it goes back up to 20 or so.

 

[sublyminull]

Have you checked the vacuum lines? Maybe you have a Vac leak. I would start there. From that point I would start looking the other componets.

I once had issue similar to this where it started small and then got bigger to where I had 0 vac. Turned out to be the t-fitting on my boost gauge line had dried and cracked. Hope this helps!

 

[codex]

This ended up being a faulty boost gauge. It sticks around -18, I checked it with another gauge and it is about -22 vacuum.