Extremely Odd Idle Problem

[KA RPS13]

So I own a 93 240SX SE Fastback, low miles and really well taken care of. I have had the car for a few months and recently I started noticing the idle fluctuating and when I came up to stops it would almost die.

I have searched around and looked at the usual suspects(maf, injectors, IAV, etc.) Today I went out searching again, and I couldnt find anything wrong no bad connections or bad grounds. So I was sitting there in the car trying to think and I was going to drive it around the block to pinpoint what could be the cause.

So I took my ebrake off and was about ready to get going and noticed when I pushed my foot on the brake the idle dropped about 100 RPM. I thought to myself thats pretty odd.

So I decided to pump the brakes at a decent speed and the idle then was dipping to 500 and back and almost stalling.

When I went around the block noticed when I pushed the clutch in to coast and hit the brakes it would dip down. Bingo problem found!

So when I went to park I noticed the power steering would cause the idle to dip really low. So this in combination with the brakes seems to be the issues here

Does anyone have any suggestions on how I would go about fixing this.

~Sean

[hendogg8]

I have a similiar problem, but not as dramatic as yours. I just get a rough idle when pressing on the brakes at a stoplight or rpm's dropping as I'm on the brakes and approaching full stop. Have you tried checking your brake booster?

[KA RPS13]

Nope I havent checked my brake booster.

[Teb74]

I'm having the same problem... Mine will actually die in fact when stopping... I was thinking previously vacuum leak?

[myzislow]

take vicegrips & pinch off vac tube to brake booster, if the issue went away its your booster

[ineedadork]

test valves?