My 95 Nissan 200sx (automatic) has a tendency to stall when I brake coming to a stop. However, if I am approaching a stop sign and put the car into neutral and then brake it never stalls. I’ve had the fuel filter replaced and the fuel pump is working fine. The idle speed is where it should be; maybe even 100rpm too high. The problem has baffled several people that looked at it. Any ideas would be appreciated.
Are you saying it never stalls or runs bad unless you put the brakes on?
When you start it up after it stalls does it idle ok.
You may have a vacuum leak in your brake booster.
The booster uses the vacuum from your engine to assist in braking, however it isn;t supposed to leak air into the engine’s intake. If it’s leaking it’ll act like an intake manifold leak.
Any hissing sounds when you brake?
It generally runs fine except for when braking. It idles at about 750rpm, but when I apply the brakes to come to a stop the RPMs dive down to about 300 and then it usually stalls. It is curious to me because the RPMs don’t dive if I put it into neutral before applying the brakes.
I haven’t noticed any hissing, but I’ll listen for it the next time I drive.
You can check for this with either of two easy methods.
You can disconnect the vacuum line to the booster, plug it, and see if the condition still exists. DO NOT go for a drive like this. Your brakes will still function, but they’ll take a lot more force.
You can check the manifold vacuum with a vacuum gage. If applying the brakes causes a sudden vacuum drop, you have a leak in the booster.
I forgot to mention this fact too (only because I’m so used to it and it is only a minor inconvenience): when I turn hard at low speeds (into a parking space usually) the car sometimes stalls. Is it plausible that a vacuum leak would contribute to this problem too?
My guess would be the brake booster vacuum leak. I suppose it might be something to do with the transmission, but you have not said any of the magic words and what you have said just does not point that way.
Not likely. The occasional stalling when turning tightly may be due to a failing power steering pump loading down the crank.
It is also possible that the engine is just weak, just too worn to have good compression in the cylinders and this good strong even combustion, and the added load of the PS pumps is occasionally stalling it. A compression check may not be a bad idea. How many miles does the engine have?
Does it stall with a jerking action – like a manual shift when you forget to release the clutch? If so you might have a problem with the torque converter lock up clutch not releasing. This is usually a sticking TC lockup solenoid but it could also be a sticking shuttle valve.
Hope that helps.
it has 125K miles
It stalls gracefully - not jerky at all. Initially I thought there was a problem with the fuel system because it felt like it was being starved of fuel, but the pump, filter, injectors are working well.
Try cleaning the Idle speed control.