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Cannot accelerate just jerks and backfires

Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 1991 PONTIAC BONNEVILLE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
Running fine then wouldn't accelerate after stopping just backfires no response when push pedal to floor. Acts like it's out of gas so checked the fuel filter and it was so clogged nothing could go through, replaced filter and wasn't much better so replaced fuel pump. Still doesn't want to run when I push down on pedal. It can get up to speed with just tapping pedal and let engine idle itself up this along with chugging and sputtering and lots of engine misses. What do I do now? Is it a vacuum thing? It backfired so bad one time it blew the air cleaner box lid off. Checked the fuel lines for crimps looks pretty good (for 28 year old wear and tear) in the engine the accelerator has two thin small shafts after cable wire and one looks a bit looser (has flat small c-washer to attach to cable wire). I don't know what it's called. Please help this is my only transportation!
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Wednesday, June 26th, 2019 AT 4:38 AM

12 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Welcome to 2CarPros.

For you to get a backfire through the intake, most likely the fuel mixture is too lean. I know that doesn't sound right because you replaced the pump and filter, but it can be a vacuum leak causing it, especially if you blew the air cleaner off.

Do me a favor, here is a link that explains in detain causes of backfiring and how to fix them. Take a look through this link. I will explain what to look for and how to do it. If it doesn't help, let me know and we'll work together on it. I will tell you that I would check both fuel pressure and for a vacuum leak first. I would also strongly recommend checking for diagnostic trouble codes.

This vehicle has what is called and OBD1 system. To retrieve trouble codes that could point us to the exact problem is very easy to do and doesn't require a scanner. Instead, all you will need is a 3 inch jumper wire or even a paper clip.

I am going to list different links to help. Take a look through them and let me know what you find. Also, if you find a diagnostic trouble code when checking, let me know what it is.

https://www.2carpros.com/articles/engine-backfires-while-running

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here is the link for retrieving trouble codes on this vehicle:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Please keep in mind, there could be other things causing this to happen. Components such as a bad crankshaft position sensor or camshaft position sensor can do it too, but that's why I need you to get codes.

Let me know if you have other questions or need help.

Take care,
Joe
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Wednesday, June 26th, 2019 AT 8:32 PM
Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 5 POSTS
Hope you can help me solve this problem. Friend says I should remove catalytic converter.
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Thursday, June 27th, 2019 AT 10:43 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Welcome back:

You can't just remove it. It would need replaced or new problems would start. Were you able to get trouble codes for me? This actually could simply be an engine vacuum leak. And yes, if the catalytic converter is plugged, it can cause it, but that is an expensive guess.

Let me know.

Joe
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Thursday, June 27th, 2019 AT 3:31 PM
Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 5 POSTS
My car doesn't have a check engine light. It does have a system monitor with picture of car in right side of dash for oil, water, battery, etc. If there's a check engine light I've not seen it. I sent a picture of my dash as I don't have check engine light, have systems monitor with oil, battery, water, etc. So can't retrieve trouble codes this way.
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Thursday, June 27th, 2019 AT 9:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Welcome back:

Did you check for the OBD port? The vehicle should have one. It was a requirement when the vehicle was made.

Let me know.

Joe
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Thursday, June 27th, 2019 AT 10:12 PM
Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 5 POSTS
Yes, but it doesn't accept guide wire to test.
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Friday, June 28th, 2019 AT 1:21 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Honestly, this is a first. I've never seen one that didn't. Can you upload a picture so I can see what you are dealing with? It would help.

Joe
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Friday, June 28th, 2019 AT 5:37 PM
Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 5 POSTS
Sent picture and could you please tell me where it would flash on my dash?
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Saturday, June 29th, 2019 AT 3:21 PM
Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 5 POSTS
Did you get the picture and message I sent?
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Saturday, June 29th, 2019 AT 4:32 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,133 POSTS
Welcome back:

I didn't receive any pictures. However, if you turn the key to the run position, you should see a engine light. It may even say service soon.

Let me know

Joe
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Saturday, June 29th, 2019 AT 6:03 PM
Tiny
CAROLYN HAWTHORNE
  • MEMBER
  • 5 POSTS
There is a service engine soon square on dash unfortunately it doesn't light up or flash. I checked the fuses all looked okay. I have the "car from hell" as I think it's possessed. Maybe I should try exorcism. Lol! The guy at parts store even gave me a code key so I didn't have to use the paper clip. Sorry for wasting your time. I'd push it off a cliff but only have liability insurance.
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Thursday, August 8th, 2019 AT 4:04 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,833 POSTS
If I can jump in here. it sounds like you may have a blown head gasket between two cylinders. I can tell for sure if can please shoot a quick video with your phone of the engine cranking over so we can see what's going on? that would be great. You can upload it here with your response.

https://www.2carpros.com/articles/how-to-test-engine-compression

Please run down this guide and report back.
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Thursday, August 8th, 2019 AT 10:14 AM

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