1999 Pontiac Grand Prix Car Keeps shutting down at odd time

Tiny
RANDY GUTTERY
  • MEMBER
  • 1999 PONTIAC GRAND PRIX
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
Our car starts and runs but quits at odd times. We hae changed the computer and o2 sensor. Now the O2 sensor is burning out repeatedly and they have no idea why it keeps burning out. This is the 3rd or 4th O2 sensor in 2 months. How they figured it out was a computer flickered with the error message and now comes up with the message. There is a weak signal coming from the sensor and that is what is causing the car to run normal and then cut off randomly. They have asked us to buy a O2 sensor from a GM dealership only if the sensor is of a different brand. I looked and the sensor they are using is the exact same as what GM sells. Which is a Bosch which is the best brand
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Friday, October 23rd, 2009 AT 7:24 AM

7 Replies

Tiny
DOCFIXIT
  • EXPERT
Hi
What was code in P0xxx format? Has fuel pressure been checked? Recent tune?Does it die hot, cold, at speed, idling? Does it die like key turned off?
Let me know
Thnaks for donate
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Friday, October 23rd, 2009 AT 9:30 AM
Tiny
RANDY GUTTERY
  • MEMBER
Hi
What was code in P0xxx format? Has fuel pressure been checked? Recent tune?Does it die hot, cold, at speed, idling? Does it die like key turned off?
Let me know
Thnaks for donate
It was tuned about two years ago. (All spark plugs replaced, all filters, all injectors were cleaned, and a few other things). It dies cold, hot, and at idle. It just depends one the situation. We have had it die going down the road at 70 miles an hour and then die when trying to put it into drive. Also if it was a fuel issue, tell if I am wrong, it would sputter to a stop but the car normally just shuts off not really sputters.
Mechanic won't give me the code!
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Friday, October 30th, 2009 AT 2:51 AM
Tiny
DOCFIXIT
  • EXPERT
Go to an Auto Zone they will do for free
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Saturday, October 31st, 2009 AT 1:33 PM
Tiny
RANDY GUTTERY
  • MEMBER
The code is P0102 MAG
Constantly scan tool shows MAF readings sticking and 1.34 sec or 1.64 gls or 2.07gls. Lan watch scope gives good back probe readings on MAF that computer is not reading. Sometimes the computer has good readings, sometimes not, w/o touching or moving anything.
This guy has replaced 3 computers and as many o2 sensors. Also replaced the battery. The car is running now but weare still afraid it will go back to it's old ways.
It's my nephews car so taking me a long time to get the info.
Not sure if this is making the connection to the oldstring, if not let me know at randy_guttery@hotmail. Com
Thanks!
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Friday, November 27th, 2009 AT 10:31 AM
Tiny
DOCFIXIT
  • EXPERT
Most likely causes for Po102 is air leak at MAF, throttle spacer, intake manifold, PCV, EGR, oil dipstick tube and oil filler cap. Also is MAF signal frequency over 1200 Hertz?
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Monday, November 30th, 2009 AT 12:40 PM
Tiny
RANDY GUTTERY
  • MEMBER
Checked everything you recommended and all OK. The car ran right for awhile after replacing the computer and o2 sensor for the third time. However last week the "check engine" light came on again. The code that came up this time was for the catalytic converter. When we brought it in originally they thought maybe it was just a miss reading or some how fuel or something set of the sensor. So they just reset the computer and told us to wait 100 miles and see if the check engine soon light came on. Well it came back on this past Friday so we are taking it in to check the code and see what it says and if it is the converter again we are going to replace it. But I want your advice one thing. What normally happens when a catalytic converter goes out? Could this be the cause of all my original problems?
Thanks!
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Tuesday, December 8th, 2009 AT 10:29 PM
Tiny
DOCFIXIT
  • EXPERT
If code is P0420 that would not cause your problem but faulty MAF could was it replaced? O2 that fails is it after CAT?
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Thursday, December 10th, 2009 AT 9:31 AM

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