Intermittent idle, rough idle, then stalls - Toyota Nation Forum : Toyota Car and Truck Forums

Savio · 02-03-2010, 05:09 PM

Hello all,

This issue is happening on a 1998 Toyota Camry 4cyl. The car has about 138k on it and has had routine maintenance. The fuel filter, spark plugs, oil, air filters have recently been changed. It also has a new radiator as well.

So starting off, this problem started last year. We were driving home on the freeway and got off of an exit. The car started to idle rough at a stop sign and we pulled over where the engine stall. We let it sit for a while and we were able to proceed driving as usual. No issues on the drive home.

It happened again while we were driving. This is already while the car is warm and have been driving. So we took it to Toyota where they said it's a possible IAC issue. It was a pretty penny to get it replaced so we came home to do some research. We stumbled upon the seafoam trick and it seemed to do the trick but after a couple of weeks. It happened again. So we decided to get the IAC replaced.

It ran fine for 3 months and then while coming to a stop, it started to idle rough again and the engine cutoff. We were able to turn it back on quickly and rough idle it to a parking lot. We let it set and it drove normally.

This is a very intermittent issue. This happened early last year around April 09, we had the IAC replaced in September09. It's happened about 6 times total but worrisome enough we don't want to get stranded. It seems as though, the IAC was not the issue and it's something else.

After reading the site, it could be a number of things:

ECTS - Engine Coolant Temp (ECT) Sensor
Ignition Coil
o2 sensor
gas pump
EGR Valve
ICM

Is it possible it's one of these?

Are there any ideas that you all know of I can check for? I have limited (very) tools to work with but I would to hear your responses on what the issue it could be.

Thanks in advance.

Savio · 02-04-2010, 11:29 AM

I have never had an issue with the engine cold. It always starts and it's only when the car is warm.

My g/f did say she smelled gas but there were buses in the area. I'm not sure if that is a symptom.

csaxon · 02-04-2010, 11:45 AM

There are 3 things that will make you stall when slowing down to a stop.

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

csaxon · 02-04-2010, 11:53 AM

Simple tests: EGR VALVE . Disconnect the vacuum hose to the egr valve.. Drive your car and see if its fixed. This will light the check engine light, when you’re done with the test, disconnect the battery to clear the light.

ENGINE COOLANT TEMPERATURE SENSOR (ECT). To confirm this connect a voltmeter to the ECT sensor and check the resistance (ohms). Turn on 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.
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.

Savio · 02-05-2010, 04:42 PM

Thanks for the info...

I took a picture of what I think is the ECTS:

I'm I pointing at the right one?

hill8570 · 02-05-2010, 04:56 PM

Quote:

Originally Posted by Savio

Thanks for the info...

I took a picture of what I think is the ECTS:

I'm I pointing at the right one?

Yeah, the sensor with the green connector is the ECT

Savio · 02-05-2010, 05:12 PM

Would I have to take it out to test it or is it possible to test it while it's in?

hill8570 · 02-05-2010, 05:50 PM

Quote:

Originally Posted by Savio

Would I have to take it out to test it or is it possible to test it while it's in?

To do detailed testing, you'd have to pop it out, but that shouldn't be necessary. To do a "is it most likely OK" test, just pop off the connector when the engine has been cooling overnight, check the resistance between the two terminals on the sensor, and compare against spec. Then drive around until it's warmed up, pop off the connector again (or, if it's warm enough, just leave off the connector after the first measurement so you're not pulling the connector off a hot engine -- that will cause you to start quite lean, and trigger a CEL, but no harm done if the engine will stay running while it warms up), measure resistance and compare to spec.

Specs are at www.camrystuff.com, Generation 4, SFI section, starting at page 48

Savio · 02-10-2010, 04:04 PM

Thanks for the tips guys. I'm hoping to go check it out this weekend since it's been raining like cats and dogs recently in LA.

As for the exhaust, is there anything I can check? I do not hear any loud noises or smell anything like it would be a bad exhaust.

Let me know. Thanks!

Savio · 04-08-2010, 07:31 PM

It just happened again today. I just bought a scanner today and plug it in next time it happens. The car definitely stalled when it was running for awhile. It happened coming to a stop and rough idled and cut off.

stingraycamry1996 · 04-30-2010, 03:27 PM

this might be a stupid question but why is my ECT connector ( the green one ) on the left and not on the right as pictured ?

hill8570 · 04-30-2010, 04:07 PM

Quote:

Originally Posted by stingraycamry1996

this might be a stupid question but why is my ECT connector ( the green one ) on the left and not on the right as pictured ?

Because when Toyota when to OBD-II on the 5S-FE (1996 model year) they moved the canister purge valve completely off the outlet and (for reasons unknown to me) switched the ECT and dash temp sensors around. Among many other changes

Savio · 05-03-2011, 09:53 PM

This must be a yearly event because just as it gets warm, it happened again today. It hit 85 today in LA.

We have not had an issue at all during the cool fall and winter months. Not sure what else to do. We took it to a mechanic specializing in Toyota's but said he could not find anything.

I wasn't able to get a reading when the car stalled but the CEL did come on when it happened but didn't show when trying to start back up after stalling.

The car runs perfectly fine other than this issue. Any other suggestions?

Savio · 05-05-2011, 11:08 AM

I'm thinking about either replacing the EGR Valve or EGR Vacuum Modulator Valve, which one should I replace first as a testing point?

Savio · 08-25-2011, 09:08 AM

It happened again yesterday, temperature was close to 83-84. The engine didn't even idle, it just simply cut off and had to roll into a store with traffic behind. Had to use the hand brake to stop the car.

From the last time I posted, the vehicle has gotten a new ECT sensor and a new fuel filter and had been running fine since then, probably because it's been cooler in the Southbay area (temps between 65-75).

I have taken this to 3 mechanics and they said they couldn't find anything wrong with it and it's hard to diagnose without a CEL.

I'm going to look at the EGR system but shouldn't that give me a CEL if there was an issue?