92 Lumina Z34 5 spd stalls when clutch pushed in

[NCChevyMan]

This problem is occurring intermittently and especially when the engine is hot.

My 92 5-speed Z-34 is running fine and when I push the clutch in to downshift or stop the car stalls. This happens repeatedly. Sometimes I hear a loud tapping. Other times it runs fine. I push the clutch in and start the car, let it out and the car runs fine until the next time I push the clutch in.

One more question...the radio stopped working. Before that it was intermittent. They ran all new wiring for the aftermarket radio which worked for a while and now does not work again. I think the indicator light on the headlight switch goes out at the same time.

Can anyone help with these?

Thanks,

Tom

[robertisaar]

the clutch issue MAY be due to crank movement(as in back and forth between the front and rear of the block)... i seem to remember that being possible with a manual trans LQ1.

non-functioning radio with non-factory radio is really a losing battle for someone to try and diagnose over the internet.

[pocket-rocket]

the clutch issue MAY be due to crank movement(as in back and forth between the front and rear of the block)... i seem to remember that being possible with a manual trans LQ1.

I remember reading about it too. Maybe have someone push the clutch at idle to make it stall and watch the crank pulley that drives the belt and see if it moves.

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[Schurkey]

How does it run in neutral?

[NCChevyMan]

Seems to run fine in Neutral. Sometimes it runs fine. Other times it stalls when pushing in to stop and even when switching gears. Sometimes check engine comes on and other times it doesn't

I talked to someone at O'Reilly and he said that there may be a problem with throttle body valve or sensor because when RPMs drop way down is when it stalls. He said idle may need adjusting or new sensor.

Any suggestions? Has anyone else run into this?

Tom

[pocket-rocket]

You could pull the IAC and clean the pintle and passage.

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[NCChevyMan]

You could pull the IAC and clean the pintle and passage.

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I am not exactly sure what those are. I am assuming the IAC is Idle Air Control, but have no idea where that is or what pintle and passage are. Do you have any pics?

What I noticed is that sometimes I push in the clutch and RPM drops down and fluctuates between 500 and 1000 rpm...with no stall. Other times I push the clutch in and it hits 0 rpm and stalls. Then two minutes later it works fine.

The idle was increased so you can hear the engine more...but that did not seem to help.

[pocket-rocket]

I don't have a pic, but you are correct. It does stand for idle air control valve. It lives in the side of your throttle body opposite of where the throttle and cruise cables connect. It's right above the throttle position sensor.

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[walterdude]

Here's a crummy pic I took a while ago... As Jon said,,,, the IAC is the top one.....
Here is a process to relearn the idle,,,, at one point that helped my 93.... I used the second method... Didn't hurt,,, anyway!!
A thorough check of all vac lines wouldn't hurt either....
good luck,,,,
Tom...

[NCChevyMan]

Here's a crummy pic I took a while ago... As Jon said,,,, the IAC is the top one.....
Here is a process to relearn the idle,,,, at one point that helped my 93.... I used the second method... Didn't hurt,,, anyway!!
A thorough check of all vac lines wouldn't hurt either....
good luck,,,,
Tom...

Thanks for the pic. Are you referring to the piece behind the vacuum tube with two bolts on the "wings" of the part? Do I need to replace it? What is the pintle and passage?

Tom

[pocket-rocket]

Yes, that is the part. I would try pulling it out and cleaning the pintle songs passage with some carb cleaner before replacing it. The pintle is like a plunger on it that moves in and out to control the air flow aroun the throttle body to control idle, like a controlled air leak. The passage is the hole it is in. It could be binding up from carbon deposits.

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[NCChevyMan]

After the IAC was cleaned the car ran well until summer hit. The engine does not race much any more. However, it still stalls once in a while and the check engine light comes on. O'Reilly Auto Parts hooked up their tester and said it was giving codes 22 and 23. Then, tonight something else happened. The car was running fine. I pulled up to a stop sign and then when I turned left it started to "chug" or make a "put put" sound like there was a leak or misfire. When I pushed the clutch in to shift gears or stop it stalled more frequently. Now it is stalling and sounds bad. Not really what I needed when I have to be at work in the morning. Has anyone experienced this problem?

Tom

[robertisaar]

22 = TPS, can certainly cause stalling.
23 = IAT, which to a lesser degree will cause issues.

[SappySE107]

I would see if your computer is updated to the latest code. There are some drivability fixes including this stalling issue, though it sounds like you have another issue as well.

[NCChevyMan]

I replaced the valve cover gaskets, intake manifold gasket, EGR and IAC...running much better.