1996 Camry 4cyl Idle/Stalling Problem?

[KenRosier]

My local garage has not been able to find the cause of this problem so it’s looking like an expensive trip to the Toyota dealer but I thought i'd run it by the forum first. The last time I visited the dealer they wanted to replace $3,200 in parts to correct a $165 problem.

This problem started over a year ago on my 1996 Camry 4cyl. Every once and a while, after driving a long distance on the highway and coming to a stop, the idle would drop down and occasionally the engine would cut out. I would re-start the car and everything was fine again. I then went and had a complete tune up done. Plug wires, dist cap and the whole bit. Though the car ran smoother the original problem never went away. Over time it became more and more frequent to the point where now it happens several times a day. On many occasions, the car doesn’t actually stall but the idle drops down very low and cycles up and down at the verge of stalling. From like 500 rpm to near 0, up and down and many of time will eventually stall.

If I put the car in neutral and rev it way up several times it will settle back to a normal idle. Also, generally, if you shut the car off and restart it, it also goes back to a normal idle.

Can anyone help me to narrow this down? You help would be greatly appreciated.

[Brian R.]

Did you ever get a "Check Engine" light when it was running rough?

[KenRosier]

Originally Posted by Brian R.

Did you ever get a "Check Engine" light when it was running rough?

No... I didn't.

[Daniel M. Dreifus]

try a short spray of TriFlow at the rectangular hole (air inlet to IAC valve) at the (inside) bottom of the throttle body.
the idle air control valve regulates idle speed (controlled by the computer)
if that valve were sticking could account for idle speed not responding correctly
TPS (throttle position sensor) could be questionable also. (tells the ECU computer when throttle is closed at idle)
check for smooth progressively increasing resistance with ohm meter
there is also a setting measured across the IDL contacts at the TPS while holding thin thickness guage in position to calibrate the point at which idle engages.
these setting are in the factory service manual under the heading of throttle body removal

[csaxon]

Some possible causes:

1) egr valve is sticking
2) torque converter not releasing
3) ECT sensor

Simple tests: EGR VALVE. Go under the hood and disconnect the vacuum hose to the egr valve.. Then drive and see if symptoms end. You will get a check engine light but you can reset it by disconnecting the battery for a minute after the test.

ECT (Engine Coolant Temperature Sensor). Connect a voltmeter to the ECT sensor and check the resistance (ohms). (take a reading) Then, start the car, let it warm and watch the ohm readings. They should decrease as the car warms up. If the readings start going up and down erratically it means that the ECT sensor is gone.

ECT These erratic readings are interpreted by the ECU like low coolant temp and creates an enriched engine condition ( to much gas ) and the car will do a warm stall. If that's the case, buy a new ECT sensor and install it. You remove the old one and put the new one on with a bit of Teflon tape.

This site has good info. Click on your engine image to enlarge it.

http://www.autozone.com/servlet/UiBr...3d8016600a.jsp

[Brian R.]

Good link

ECT is pretty likely

[csaxon]

This has ECT info

http://www.autozone.com/servlet/UiBr...3d8013ec3f.jsp

[KenRosier]

My thanks to all for the great information. I'm planning on looking at these possible issues tomorrow (Saturday) so I'll let you know what I find.

Cheers, Ken

[Jmore]

I have the same problem with my 98 4cyl camry. I will be on the highway
doing about 65-70 and I feel a hesitation. If I pull over the idle goes down to about 200-300 & then stalls. If I sit there 1 min & restart it is fine. I can also put in neutral (while moving on highway) and rev to about 5500. This will clear the problem. It happens about once aweek.
It does'nt matter how fast I'm going 25 --75 mph ..it happens.
I just found this web acouple weeks ago..I read the posts and will try some of their ideas soon. thanks & good luck

[popeye08]

My 96 camry 117k, has idle speed stall, idle speed flunctate(erratic, up to 2000rpm when wait for traffic light some time), EGR valve insufficient flow Code 401

I cleaned IAC valve, actually I damaged one of the philips screw that secure the valve and can not uninstall the IAC, so I have to take away the air intaker and start the engine and spray some O'Reilly Carb&Throttle body cleaner in that hole, engine will sound strange and almost die but every time don't spray too much it can still running. After 4-5 times. The engine stall problem has totally gone.

And then when the idle speed was flunctate, I disconnected the ECT ( Engine Coolant Temperature senser, green one), the engine was stable. So after I changed the ECT, idle speed is very stable and the engine is very smooth

Even though now I still leave the check engine light on for the EGR problem, it really doesn't affect the engine at all. So I don't think EGR valve can make engine stall or unstable. And I also talked with one guy in the Toyota dealer, he think EGR can only cause tough idle and more gas. That is.

Thanks you every body who contribute the ideas and experiences!
It really help me a lot.

[KenRosier]

This weekend I cleaned the IAC valve (idle air control) and so far the problem seems to be gone. Thanks for all the great input.