1999 PONTIAC GRAND AM CAR BUCKING AND JERKING ON ACCELERATI

  • Tiny
  • Bookgirl37
  • 1999 Pontiac Grand Am

Engine Performance problem
1999 Pontiac Grand Am 6 cyl Automatic 143000 miles

I hope you can give me some answers. My car has been idling rough for a while & has been getting poor gas mileage. We thought it was the EGR valve, replace that & the problem still exists. Two days ago after getting fuel, the car started jerking and bucking when I would accelerate. If I decrease pressure on the gas pedal, it stops. The service engine soon light has been on for a while. We took it to AZ and the it came back with a code for multiple misfires. My plugs & wires are new, they tested the Ignition Module & it is fine. Could these problems be caused by clogged Fuel injectors and it just needs to be cleaned? I do buy really cheap gas!

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Saturday, January 10th, 2009 AT 10:16 AM

8 Replies

  • Tiny
  • Dave H
  • Expert
  • 13,547 posts

Hello. Thanks for the donation. Much appreciated

This could be due to injectors clogging. Add a good fuel injector cleaner. Check/clean/replace air filter also and you could also check the fuel pressure. Let me know if the fault still occurs after cleanig

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Saturday, January 10th, 2009 AT 11:39 AM
  • Tiny
  • Bookgirl37
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I took it and had it cleaned professionally & it is still doing the same thing. My husband did find a loose spark plug also. It is running BETTER, but still jerking some.

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Saturday, January 10th, 2009 AT 1:47 PM
  • Tiny
  • Dave H
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May sound a silly question but I gotta ask. He did check all the plugs. Did they check fuel pressure. Could you also tell me the engine size of vehicle?

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Saturday, January 10th, 2009 AT 10:13 PM
  • Tiny
  • Bookgirl37
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He did check all of the plugs. I have a V-6.

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Sunday, January 11th, 2009 AT 6:55 AM
  • Tiny
  • Dave H
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  • 13,547 posts

Hello. Thanks for the plugd info. By engine size I meant 3.2L 3.5L etc. Also could you tell me which type of plug wire you have. COP coil on plug or standard HT leads going to a large coil. And is the MIL light showing again on the dashboard?

Thanks

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Tuesday, January 13th, 2009 AT 5:51 AM
  • Tiny
  • Bookgirl37
  • Member

I have a 3.4 liter engine. I think my plugs run through a large coil. The service engine soon light is still on & it is popping the same code of P0300. My husband is going to replace the plugs, wires and coil this weekend, as well as putting on a new fuel filter. I am really hoping I do not have a bad fuel injector.

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Tuesday, January 13th, 2009 AT 7:33 AM
  • Tiny
  • Dave H
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Ask your hubby to check CKP wiring and perhaps remove and clean sensors ! I would expect if it was a bad injector you would gat a misfire code for the actual cylinder/injector that is misfiring ..let me know

Crankshaft Position (CKP) Sensor (7X) (3.4L)Lower right side of engine. See Fig. 3 .
Crankshaft Position (CKP) Sensor (24X) (3.4L)Left front of engine. See Fig. 3


http://www.2carpros.com/forum/automotive_pictures/266999_ckp_4.jpg

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Tuesday, January 13th, 2009 AT 8:31 AM
  • Tiny
  • Ashes
  • Member

Transmission.
Mine was doing the same thing last month. Automatic transmission ground my clutch disks to pieces. Not a cheap repair.

If this is the case for you as well, I recommend you replace your waterpump while your at it, since it sits directly under your tranny. How mad would you be if that $50.00 part blew out after you waited the time it took for them to get your tranny back in your car?

Best of luck, really hope I am wrong!

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Saturday, February 7th, 2009 AT 10:17 AM

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