2000 GMC Jimmy Surge

Tiny
FOSTERJ
  • MEMBER
  • 2000 GMC JIMMY
Engine Mechanical problem
2000 GMC Jimmy 6 cyl Four Wheel Drive Manual 150.00 miles

I have a 2000 GMC Jimmy when driving at a steady pace the RPM's surge up 100-300 RPM.
The repair shop told me it was the mass air flow sensor. They replaced it at 356.00 as soon as the car hit normal operating tempter and I was a couple miles down the road the surge returned like it always did? The RPM's do not surge when I am accelerating
only when I level off. And yes the air conditioning is off. Thanks
Tuesday, May 5th, 2009 AT 8:21 AM

7 Replies

Tiny
DOCFIXIT
  • MECHANIC
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Hi
At what speed does this occure? Have you tried putting trans in D3 see if surge goes away?
There are about 25 possible faults that can cause surge at steady speed. Did you return to shop that did repair?
Let me know
Thanks for donate
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Tuesday, May 5th, 2009 AT 9:45 AM
Tiny
FOSTERJ
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It usually surges around 35mph and up mostly around 45mph. It surges about 30% of the time at a steady RPM. If I am going 45mph at a steady 2000 RPM it will jump up to 2200 RPM and drop back down and then jump back up anywhere from 2100-2300 RPM and back down again. The shop seem cluesless they even tried to say I must have been driving around with the air conditioning on. Now I am a little bit mechanically inclined and built a few rods in my day and I think I know when my air condtioning is off.
Thanks for any insite you can give me.
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Tuesday, May 5th, 2009 AT 11:58 AM
Tiny
FOSTERJ
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Sorry I forgot to answer your first question yes it will also surge in D3 as well
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Tuesday, May 5th, 2009 AT 12:01 PM
Tiny
DOCFIXIT
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Other than the MAF was any repair made before surging? Have you owned truck new? Has initial engine timing been checked? Stock exhaust? Loos of fuel milage?
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Tuesday, May 5th, 2009 AT 12:18 PM
Tiny
FOSTERJ
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I bought the car from my sister who bought it new and always took good care of it. All the maintance and oil changes where done on time. The vehicle is totally stock. She did have the Transmission serviced not long ago as well as the fuel pump being replaced.
The timing has been checked and is correct at this time.
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Tuesday, May 5th, 2009 AT 12:36 PM
Tiny
FOSTERJ
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The new MAF did make the vehicle run better and now gets better gas mileage and seemed to help the surging a little bit but did not eliminate it.
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Tuesday, May 5th, 2009 AT 12:39 PM
Tiny
DOCFIXIT
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I think the O2 sensors maybe the fault. If MAF faulty the fuel was rich for sometime and fouled O2 so at steady speed PCM is hunting for proper fuel mix. Well that's my theory. Have them scaned see if they are in range.
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Tuesday, May 5th, 2009 AT 12:53 PM

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