Backfire, then it stalled and started up roughly

LLOBECK

MEMBER
2000 CHEVROLET ASTRO
3.4L
6 CYL
AUTOMATIC
150,000 MILES

Driving and van started to back fire, stopped at a light and then it stalled. Van started chugging last year while driving, but after I passed first gear it runs pretty good. I have done a lot of work to this van and no one seems to know or figure out what is going on. I had catalytic converter replaced, spark plugs and wires replaced (twice), cap and rotor replace (four times), 02 sensor, gas cap, waterpump, radiator and hoses replaced, fuel filter replaced. Please help. Thank you, Lynne

6 Replies

HMAC300

MECHANIC
48,601 POSTS

Scan for codes and check fuel pressure with a gauge auto parts rent it. then ccheck for a vacuum leak and compression here is an article on fuel pressure..
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

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Friday, September 30th, 2016 AT 6:48 AM

RENEE L

ADMIN
1,257 POSTS

Hi Lynne,

If you decide you would like to conduct the scan yourself here is a link to an article that features written step by step instructions and pictures explaining how to do the scan yourself, also I have included a link to our YouTube channel with a how to video on code scanning. Most scanners are inexpensive to purchase, you can purchase one online from sites like Amazon.com

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

https://youtu.be/YV3TRZwer8k

Once you have the codes please get back to us so that we can further assist you. We are always happy to help.

Thank you for visiting 2CarPros.com.

Kindest regards,

Renee
Admin

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Friday, September 30th, 2016 AT 4:03 PM

LLOBECK

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3 POSTS

The code from Auto Zone is P0420

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Saturday, October 1st, 2016 AT 3:13 AM

HMAC300

MECHANIC
48,601 POSTS

420 is a bad catalytic converter but that won't cause a backfire that I know of. But I f you have an air leak in exhaust system prior to converter or and O2 sensor screwing up will give the same code if it wasn't erased. Just for giggles check the firing order on this. If you don't have the dist cap that is pictured it is wrong and that may be your backfiring because it's wired wrong.

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Saturday, October 1st, 2016 AT 7:31 AM

LLOBECK

MEMBER
3 POSTS

Cadylitic converter has been replaced. Cap & rotor has been replaced 4 times. 02 sensor replaced. Muffler had not been replace, would that cause backfire & rough running if there is a hole in exhaust pipe or muffler?