Stalls returning to idle?... Help please!

[1995mtxsho]

Alright, this winter crap cand bugger off for all I care... anyways...

95 MTX

Ever since we got a cold spell here, the car has been having issues before it warms up.
1. It idles very low, say between 500/800 RPM.
2. It does not like to return TO idle, and will stall upon stopping more than half the time.
3. Off-idle, taking off from a start, it will flutter and try to stall.

Symptoms go away when up to operational temp.
Check engine light came on once, was out upon next restart.
I have not pulled codes yet, Its cold, and the CEL is not on.

Perhaps I am wrong but I assume that if the CEL is not lit, there wont be any codes to fetch? I know reletively little about OBD I.

Figured I would try pulling codes after posting.

It seems like the IAB valve may not be working properly...

Any ideas/experiences would help.

 

[SeanMc]

I had a myriad of codes before...with no CEL. Check your codes, and you might be suprised.

 

[1995mtxsho]

Alright, I was pleased and horrified about the codes I pulled from the KOEO test.
Pleased because there was only one hard code, and only one memory code.

Horrified because of what the memory code was.

Hard code was...
-114 - ACT/IAT sensor out of range
--Not a biggy, I replaced the sensor because it was cheap and 12+ years old.

Memory code was...
542 - Fuel pump open, bad ground or always on
--This one startled me at first, but after searching it seems its not a big deal on an MTX?

I did not run the KOER test, as I was at work and didnt have the procedure with me.
I will update with anything on that when I can get a chance to do it.

Anyone have personal experience with either of these codes?

Can the ACT/IAT Sensor cause stalling?

I havent driven it very far but right after I reset the computer.
It seemed better, but it may not be the problem because of it being intermittent before, and the lack of driving it after resetting it.

 

[92inPA]

Your problems seems likely to be an air management issue. The IAT change could be your fix. Also, you may want to check your MAF. Buy a can of MAF cleaner and give it a good cleaning.

 

[93rev2sev]

The ACT AIT is the air temperature sensor. It will read "out of range" when you pull codes on a cold engine. Thats normal.

I would also suspect the MAF Sensor. The MAF sensor tells the computer how much air is entering the throttle body. If the sensor is unable to report the correct amount of airflow to the computer, the computer will have a hard time regulating idle.

First thing to do would be to look for vacuum leaks on the intake. My guess is that air is entering the engine without the knowledge of the MAF sensor. Make sure the rubber intake hose is secure at the throttle body.

 

[1995mtxsho]

Well the car idles fine, and is fine for a little while after cold start.
Then it will idle down at a stop half the time, the other half it will sputter and stall.
But, after a few minutes while driving I can stop at a stop light and it will idle down fine, and while idling if I even BREATH on the gas pedal it will cut out and try to stall. Only feathering the gas and pushing the pedal down quite far will overcome this so i can drive away.

KOER Codes:
I ran the test twice, the first time gave me these;
412
116
114

Second time, engine was cooler, as I needed to thaw myself out in between tests, was;
116
114

Balance test gave 9.

Anyone have anything they can suggest?

 

[93rev2sev]

Vacuum leak
MAF dirty or burned out (2 elements in MAF, one can be burned out I think)
Plugs and wires (check for oil in wells and proper spark plug style and gap)
TPS (doubt it, but search around for throttle position sensor test)
Thats all I can think of. My car did the same thing and it was the MAF

 

[1995mtxsho]

Wont a bad MAF throw a code?

 

[93rev2sev]

Also check out this thread.
http://www.shoforum.com/showthread.php?t=71933