1997 Pontiac Sunfire stalling and bucking

Tiny
JOHNBOWZER
  • MEMBER
  • 1997 PONTIAC SUNFIRE
  • 4 CYL
  • FWD
  • MANUAL
  • 130,000 MILES
I have a GT 2.4, it will intermittently lose RPM in 1st and 2nd at low speeds, even at idle, will drop below 1000 rpm, run rough, sometimes stall, and be hard to start again. When you give some throttle, it konks out. Intermittent problem though. Had recent throttle pos sensor and EGR replaced. I saw posts suggesting IAC valve?
Possibly related. Also when accelerating more agressively (only in 2nd though?) It will buck, not always, but frequently, and it can be mild or wild when it does. I saw posts suggesting EGR, TCC solenoid?
Friday, February 1st, 2008 AT 7:18 PM

6 Replies

Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,749 POSTS
No egr, no iac, no tcc. Does your check engine light come on? What codes? Sounds like ignition breakdown.
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Friday, February 1st, 2008 AT 7:22 PM
Tiny
JOHNBOWZER
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  • 4 POSTS
No check engine light. It was acting up earlier today, but when I had it out a short while ago it ran fine, it's been like that for a week and half.
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Friday, February 1st, 2008 AT 7:41 PM
Tiny
JOHNBOWZER
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  • 4 POSTS
I took off and cleaned the IAC and the problem with low idle/stalling has not returned. So perhaps it was the IAC.
The bucking in second gear when accelerating even a little aggressively is still there, only in second. Wouldn't ignition breakdown cause a problem when running in idle or in any gear, 1 thru 5?
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Wednesday, February 6th, 2008 AT 4:51 PM
Tiny
MASTERTECHTIM
  • MECHANIC
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A idle air control valve cannot cause a bucking when accelerating, as soon as the throttle is depressed it bypasses the iac. I dont know why the bucking only happens in second gear, it must just be coincidence because the computer does not know what gear the car is in. This engine uses a ignition coil cover that acts just like a distributor cap, if this car came into my shop I would replace the coil cover and the spark plugs and the wire boots. Hope this helps
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Wednesday, February 6th, 2008 AT 4:56 PM
Tiny
JOHNBOWZER
  • MEMBER
  • 4 POSTS
OK thanks. Which part is that? This diagram showed part 7 as the cover, but is the cover to which you refer part 5, which is identified in the diagram as the ignition coil housing...


https://www.2carpros.com/forum/automotive_pictures/151935_Image1_2.jpg

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Thursday, February 7th, 2008 AT 3:15 PM
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,749 POSTS
#2 is the coil and yes #5 is the coil cover. Also #6 comes as a kit with parts for all 4 cylinders.
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Thursday, February 7th, 2008 AT 4:10 PM

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