Poor acceleration '02 Impala

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  #1  
Old 07-10-04, 08:28 AM
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Unhappy Poor acceleration '02 Impala

Acceleration on my 2002 Impala (72k miles) is getting worse and worse. I first noticed it when accelerating up hills on the highway. Now, it's getting worse, even when trying to accelerate up a hill from a stoplight -- at 15 to 20 mph. This morning, I replaced the fuel filter. That seems to help a little at the higher speeds, but hasn't appeared to do much at lower speeds. What would be some causes for these symptoms? The transmission feels and sounds fine. I guess it could be the fuel system or the air flow system (MAF or filter). Any thoughts on what could be causing it? How would I know if the fuel pump is going bad?
 
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  #2  
Old 07-11-04, 03:07 PM
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Check the fuel pressure with a guage and also the catalytic converter for a restriction.You have checked the air filter,correct?A dirty maf sensor could cause the problem also.
 
  #3  
Old 07-12-04, 05:49 AM
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Thanks for the reply. Hopefully it's nothing major. I don't know much about Chevys. I have a few questions.

1. I have not checked the air filter, but will do so. Will a dirty air filter hinder performance that badly?
2. I rapped on the cat, but didn't hear anything rolling around (just had one go bad last month on muy Jetta). How can I check if it's plugged?
3. I suspect the MAF is right next to the air filter. Is cleaning something I can do myself?
4. I can go to Autozone and they can read the ODBII. My check engine light is not on, but maybe there may be a trouble code in the computer.
 
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Old 07-12-04, 03:03 PM
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#1 yes it can #2hitting a convertor doesn't alwaysn yield an answer it needs to be removed or tested on the car at an exhaust shop.#3 if your car has a 3.4 it is right next to the air filter housing,if a 3.8 it's in the throttle body itself.Yes you can clean it yourself with carb cleaner or better yet brake clean.#4 By all means have the codes checked but do it before you have touched anything else or the results may be self induced.
 
  #5  
Old 07-13-04, 09:39 AM
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Thanks for the response. Ended up taking it to my mechanic who said the codes are consistent with a plugged cat. What causes the restriction?

Also, I've got less mileage than the 80k Federal warranty. Will the restricted cat need to be replaced and typically fall under this warranty? I have to take it to the dealer service dept. for the repair and I typically get the runaround there...
 
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Old 07-13-04, 05:20 PM
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If the cat has failed under the 8yr 80k warranty it should be at no charge.What are the code #s.This is very important for a warranty claim.Do you have a remote start installed on the car?
 
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Old 07-14-04, 05:46 AM
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The codes were p0404 and p0327. They also said they found the exhaust restricted.
 
  #8  
Old 07-14-04, 02:59 PM
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p0327 is a knock sensor code if it is faulty it could cause the lack of power you have.Disconnect the knock sensor and see if the power returns.If you go to a dealer to have the cat checked and it's something else causing the problem not under warranty you will pay.
 
  #9  
Old 07-26-04, 08:18 PM
lp_spark
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Originally Posted by markdiy
Thanks for the response. Ended up taking it to my mechanic who said the codes are consistent with a plugged cat. What causes the restriction?

Also, I've got less mileage than the 80k Federal warranty. Will the restricted cat need to be replaced and typically fall under this warranty? I have to take it to the dealer service dept. for the repair and I typically get the runaround there...
You probably fixed this by now, but just for info if others are searching for an answer.

I brought my 2001 chevy Monte Carlo SS into the dealership today and just picked it up. The syptoms were identical to yours. It turned out to be a plugged cat converter. The mechanic said that although it's rarer in the monte carlos, it's extremely common in Impalas and they see a lot of them come in. Most of the time the cars can't even accelerate over 30 mph.

The repair fell completely under the emissions warranty and I didn't have to pay a dime. They replaced it out completely. I also only have 30,000 miles on my car.
 
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