When my brake is un-pressed my car idles ~1.3k. If I press the brake it drops to 750.

Any ideas?

Obviously it's vacuum but I don't know how to find out where. Any ideas about where?

91 Integra converted to Non-ABS.

 

most shops can smoke test for vacuum leaks.. if you look around online, you may be able to find a vacuum diagram for your set up, then go and check everything

 

I have to diagnose myself. Do they use a smoke machine?

How would you test vacuum?

Unfortunately before I put my motor in my car I put a Hondata Intake Manifold gasket on it. Do these symptoms line up with IM leak? Is it possible a leak at my brake booster causes this?

Hoping the wisdom of the masses will save me.

 

Why don't you get some carb cleaner and start spraying everywhere there could possible be a vacuum leak with the engine running? Worrying about an intake manifold is unproductive and just a random guess which defies all troubleshooting steps.

 

Hmm, I never gave it much thought but my rpm's raise when I hit the brake. I will have to check it out when I get home.

 

Thank you I shall. I suppose I'll be looking for bubbles? Haven't done this before.

 

No the carb cleaner will cause your motor to rev if it is able to leak into the manifold.