anil111
Registered: 08/24/09
Posts: 3
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| #1 |
stalling problem 1995 Buick Lesabre -custom, 6 cyl, auto, 128000 miles When cold start the engine races a little more than past 5 years. does not stall then. 1-3 miles of driving car stalls when right foot goes from gas pedal to brake. sometimes even stalls when moving and gas pedal is relaxed or the foot is off the pedal but not on brake. while moving and stalled if I put in neutral and start it while moving , it has started every time in last 50+ times and then it does not stall when car is to a dead stop. Also when I use left foot on brake and right foot gently on gas pedal to drive or to stop car does not stall. Any ideas for the reasons? |
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MasterTech
Super Moderators
Registered: 06/02/09
Posts: 38
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| #2 |
I think you have a sensor problem causing your stall. Most likley a Mass Air Flow sensor or Idle Air Control valve.
The Mass Air Flow sensor measures how much air is coming into the engine, it uses this measurment to control fuel managment ,so a bad reading will cause a stall when letting off the gas .
The idle air valve controls how much air is allowed at idle, if this valve is sticking closed then you will have a stall when letting off of the gas.
To isolate the problem you will need to have the engine computor scanned to read these sensors when the engine stalls. If you want to take a shot and guess I would replace the Mass Air flow first.
YourAutoAdvisor offers a great online repair manual by alldata.com . This online manual will give you step by step instructons on checking and replacing either one of these sensors. Both of these can be replaced at home with no problem.
Just click the link above to read more about AllData.com
Let me know how you make out or if you have any more questions
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anil111
Registered: 08/24/09
Posts: 3
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| #3 |
that was nice of you to reply so soon.
I looked into price of these Mass Air Flow sensor and Idle Air Control valve.
and they run from $200 to 400.
However reading about them it seems a lot of work to replace but may not correct the problem.
Agreeing with you about above disticnt possibility a Q comes to mind.
Why is it that the car does not stall when both feet are used to drive and right one barely touches the gas pedal? If so, is it possible it may be due to linkage from gas pedal to engine gas throttle? Also it starts immediately and then runs fine till next stall driving with one foot.
Again thanks for your excellent suggestion.
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MasterTech
Super Moderators
Registered: 06/02/09
Posts: 38
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| #4 |
This is a great question and one to think about! The reason the car does not stall is because when you have one foot on the gas you have the throttle slightly open and the RPM'S are slightly raised.
This does make me think that the Mass Air Flow sensor is not the problem because the MAF sensors usually cause a hard or no start condition after it stalls.
One thing you can do is clean the throttle body, excessive carbon in the throttle will block the air flow and cause the engine to stall.
Another thing to check is leaking vacuum lines at the engine , leaking vacuum lines will cause a stall and could also cause a higher idle when cold.
Also a sticking EGR valve can also cause a stall at idle. A dirty or sticking Idle Air Control Valve is a very good possibility as I mentioned before. The Idle Air actuator controls the amount of air is allowed into the engine at idle.
Let me know what you find
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anil111
Registered: 08/24/09
Posts: 3
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| #5 |
great suggestions. All are a possibility.
Considering your notes I am thinking it could be vaccum line leak. Hard to find the leak.
This I think is because the car does not stall when cold or restart after stall.
I have never removed the throttle body but cleaning them as you have suggested makes good sense.
Car is due for state inspection end sept. I may wait and see what state finds or does. May be get some free check up and readings.
You have great suggestions . Thank you.
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