Car stalls sometimes when I push the clutch in

[AR31TU]

I picked up a 91 fastback recently. Runs strong, no big problems except this.

Sometimes I'll accelerate and just coast, pushing the clutch in. Sometimes the revs come down really fast and the car almost stalls before the RPMs come back up. Sometimes the revs go down really slow and fluctuate around 1000 or so before going down to normal idle.

ANy idea what this might be? The only non-stock part of the car is a really crappy e-bay intake. There's some disconnected hoses that look like they should go into the intake.

Anybody got a stock air intake they wanna sell me? x-D

[AmoebAssassin]

Most 240sxes will have this problem at one point or another.

On my car it was a faulty coolant temperature sensor, or rather that the connection to the harness was rusted over. A little wiggling of this sensor fixed my car's idle and stall problem, but if yours is gone you may have to replace the sensor entirely which is a minor job at worst.

The coolant temp sensor is the red-plugged sensor located in the coolant stream to the right of the upper radiator hose.

If cleaning the sensor connections or replacing the sensor entirely doesnt fix your problem, move on to check that your EGR valve is not stuck open. If everything checks out here, your IACV (idle air control valve) needs to be removed and cleaned with carb cleaner. I hope for your sake it's not your IACV because that's a PITA job unless you have tiny hands.

If that STILL doesnt solve your problems, download the FSM and look at the parts I skipped.

[S13 240SX]

does your car start fine on cold starts?

[kamikazestorm420]

mine was an unplugged aiv.

removed that sucker and my idle stayed rock solid when i put it in neutral.

before i did that, it used to stall unless i heel and toed every single stop.

[AR31TU]

My car seems to start up fine. The starter sounds a bit lazy but all my friends 240s seem to sound that way anyway.

[TheOne]

you could also check your coolant, check the reservior tank to see if its kinda low, that shouldn't be a problem though.(if there's air on the coolant lines that help with the idle, the car will try to stall whenever you push the clutch in, it has happened to me before, since my car has a bad hg)

so it could be your IACV or AIV, or the coolant temp sensor.

[MoogieBoogie]

My car seems to start up fine. The starter sounds a bit lazy but all my friends 240s seem to sound that way anyway.

I hate to bring a thread back from the dead, but I just started having this problem too.

Were you able to solve your problem? Mine stalls all the time on the highway whenever I leave the shifter in gear and push the clutch in. If I push in the clutch and take it out of gear, it'll drop to a really low rpm (as low as ~100) and then go back up to about 600-800 rpms.

AmoebAssassin, the coolant temp sensor - how did you pinpoint the problem to this? My Maxima had a problem with this coolant temp sensor, but the symptoms were stalling (regardless of clutch-in or anything else) AND it wouldn't even accelerate at times.

Any suggestions?

Thanks,-Brian.

[AmoebAssassin]

AmoebAssassin, the coolant temp sensor - how did you pinpoint the problem to this? My Maxima had a problem with this coolant temp sensor, but the symptoms were stalling (regardless of clutch-in or anything else) AND it wouldn't even accelerate at times.

Basically, I downloaded the FSM and went through all the major steps--EGR check, IACV check, injector check, spark plug/ignition check...nothing worked, so I searched the forum for something like "stalling" and noticed the coolant temp sensor was implicated several times,. I went out to my car and went to remove the sensor, but I couldnt because of the metal clip (i was a n00b at the time and didnt want to break the connector) but the wiggling motion of me trying to seperate the clip fixed it.

[nopaintsls]

sorry... i keep hearing FSM sorry for being a noob at this but where can I d/l the FSM at?

[AmoebAssassin]

Do a search for "FSM" and you can find the download link

[KADreams]

You can get a new harness connector with the pigtail at the dealership for like $15.

[MoogieBoogie]

Thanks guys for the help.

As soon as I install the new coolant temp sensor, I'll post the result here.

-Brian.

[AR31TU]

Sorry to bring an old one back to life.

I fixed my idle by cleaning out the MAF. Now I have another odd idle issue to deal with, but my car doesn't stall anymore!

[S13FX]

You know what I m glad you fixed your problem; I had the same issue when ever I was at a stop and pushed my clutch in or let it go my car would almost die. Well it took me a while but I figured it out. One of the seals on my slave cylinder was going and it created a huge vacuum leak when ever I press the pedal in and out. I figured that out when i noticed my Clutch master reservoir was empty, and I freaked out because I was like damn now I got air in my system.

But as soon as I added some break fluid I had my friend pump the clutch while watching the slave master and what do you know one of the seals was leaking. But at least adding the fluid while he was pumping the clutch got the air out. The leak wasn’t really major it basically required me to add brake fluid once every like 3 weeks.