engine sputters when I hit the breaks and eventually stalls

[bagnasco]

Hey guys. I would really appreciate the help if you can give it.

A little bit about my car first.

My car is a 1990 Nissan 240sx with an SR20DET "Black Top" engine, cold air intake, T25 turbo, and a bunch of other stuff done to it.

My problem is.......everytime i am driving around town, I will push the clutch in and hit the brakes to come to a stop at a red light. Well, when I do this my tachometer drops from a normal 750 rpm to 1000 rpm to 500 rpm and sometimes down to 0 rpm where it stalls....obviously.

I got home, opened my hood up and checked the brake fluid......It is a rustic brown color but it is still full. I havent flushed the brake system yet until I get an answer that maybe it needs new brake fluid.

After checking the brake fluid and seeing that it is still full, I turned the car back on, let it idle at 900 rpm (normal) and then hit the brake. I noticed everytime I hit the brake the rpm gauge would go down to about 700-800 rpm. This makes me think maybe its the alternator when the brake lights come on or maybe I need a new brake cylinder......but then I got to thinking that when I brake with the car still in gear (not in neutral) the tachometer does not go down to 500-0 rpm. This only happens when I disengage my clutch or shift the car into neutral.

Any help would be appreciated.__________________

[spddemon]

So it doesnt happen if you dont push the clutch? Like if you keep it in first and stop

[bagnasco]

well if i stop in first gear.....I have to have the clutch pushed in otherwise it will stall. And because I have the clutch pedal pushed in, then it is in neutral whether the gear shift is in first or second or third or fourth or fifth.

If I was to not push in the clutch, I noticed the idling does not go down and almost stall out the engine. But as soon as I press the clutch in, it's in neutral and the car goes to its normal idling rpms (700-1000). But then I hit the brake and it starts to sputter.

Could it possibly be a vacuum leak or something?

[ShaunakaRichard]

Ummmm kinda common knowledge if you don't push in the clutch when coming to a stop your motor dies if its in gear. Thats the basics of a manual transmission......

[bagnasco]

I didnt mean to sound like a smartass in my last post. Sorry if it sounded that way. I can downshift and it won't stall. As soon as I push the clutch in or shift it to neutral and then hit the brake, the tachometer goes down to 500-0 rpm.

Do you think maybe its a bad brake master cylinder or brake booster?

[spddemon]

It could be a vacume issue in your brake booster, but reading your first post again makes me think transmission or clutch. idk I would have to see it for myself.

[bagnasco]

I took it to Tires Plus last Saturday. They did an engine diagnostic test on the car and found out it was a bad brake booster. They special ordered the part. It got there Sunday, and I got it replaced yesterday (Monday).

The car no longer stalls when I brake. So that's good. But now I have a turbo manifold leak.