While driving and trying to accelerate it hesitates and acts like it is going to shut off

Tiny
NEWRED5
  • MEMBER
  • 2002 SATURN L300
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 115,000 MILES
My car starts and drives great but when I am going say fifty or so miles per hour and I give it gas (tromp on it), they car attempts to stall out and act like it is going to shut off. Sometimes the check engine light flashes indicating a misfire. Any ideas? I pulled the plugs and they are relatively new. Thanks
Friday, April 3rd, 2009 AT 8:09 PM

7 Replies

Tiny
NEWRED5
  • MEMBER
  • 7 POSTS
Also, when this backfire is happening, if I back off on the gas pedal they car returns to normal.
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Saturday, April 4th, 2009 AT 7:29 AM
Tiny
JASONRAY
  • MECHANIC
  • 213 POSTS
It sounds like it is 'leaning' out. Which means the fuel system cannot keep up with the demands of the accelerator. I would check the fuel filter first if it is accessible. If not, the problem could be the fuel pump. We need to check fuel pressure but unless you have a fuel pressure gauge, you will probably need to take it to a shop. Do not let the fuel pressure alone confuse you. You can have the proper fuel 'pressure' but there is also a spec for fuel 'volume'. You have to have the correct 'amount' of fuel to the injectors under the correct amount of pressure for it to work right. Especially under hard acceleration. Either way, it sounds like a fuel problem based on the description.
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Saturday, April 4th, 2009 AT 9:04 PM
Tiny
NEWRED5
  • MEMBER
  • 7 POSTS
Thank you, that was my first thought. The car is at my friends house (he is a backyard mechanic) and he is checking it out for me. I will keep you up to date.
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Saturday, April 4th, 2009 AT 10:10 PM
Tiny
NEWRED5
  • MEMBER
  • 7 POSTS
Well, put a fuel filter on it and it does the same thing. When putting a load on the car it does not seem to down shift unless you back off the pedal. Thought it might be a slipping transmission so I went to a honest local transmission place. They scanned it for codes and could not find any transmission codes. They went for a ride with me and watched the computer scanner while I drove it and made it act up. Again no codes to be found. He mentioned it seemed like maybe it was plugged converter as it seem to act a bit that way( would not a plugged converter set of a check engine light?). When we got back he checked the engine for any stored codes and found five:
p0402- excessive EGR flow detected
p0300 Engine misfire detected
p302 cylinder 2 misfire detected
p304 cylinder 4 misfire detected
p306 cylinder 6 misfire detected
No check engine light are on in the car even though it is now acting up. Any ideas?
Would you take it in and get an engine scan?
Would you wait for the cars drive cycle to see if the check engine light comes on again after it was cleared?

Thanks
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Monday, April 13th, 2009 AT 12:18 PM
Tiny
NEWRED5
  • MEMBER
  • 7 POSTS
While driving the car the check engine light did come on today.
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Monday, April 13th, 2009 AT 6:08 PM
Tiny
NEWRED5
  • MEMBER
  • 7 POSTS
It put out a code P0421- warm up catalyst, low efficiency. Any help here?
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Tuesday, April 14th, 2009 AT 6:44 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
With all of the misfires on one side of the engine you may need to look at what they all share. The P0402 may be dumping too much back in the engine, depending on how it is routed may lean out that side. I have attached some diagrams that may help you figure out why you are getting that code. Sometimes one issue creates other codes,

Check out the diagrams below and get back to us.
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Wednesday, September 19th, 2018 AT 5:40 PM

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