Loss of Engine Power?

Tiny
JERADWARE
  • MEMBER
  • 2002 CHEVROLET IMPALA
My 2002 chevy impala has lost a lot of power. It accelerates strangely. If you put the petal down all the way the rmp's get high but the car doesn't accelerate as much as it should be. I know the intake manifold gaskets are leaking and I have scheduled to have them replaced. I recently have changed the spark plugs, wires, air filter and fuel filter. The car is not throwing any check engine lights. The problem came out of nowhere it went from accelerating normally to this.

Thanks
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Tuesday, April 1st, 2008 AT 9:57 PM

43 Replies

Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Sounds like you have a cat converter plugging up. Here are two guides to help us find the problem

https://www.2carpros.com/articles/engine-has-low-power-output

and

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please run down these guides and report back.
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Wednesday, April 2nd, 2008 AT 7:22 AM
Tiny
JERADWARE
  • MEMBER
  • 2 POSTS
You nailed it, the cat had broken apart and clogged the exhaust system. I love this site.
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Wednesday, April 2nd, 2008 AT 1:24 PM
Tiny
IGGI71
  • MEMBER
  • 5 POSTS
MY SOLUTION

Problem was solved by changing Cat Converter ($250) in Maineken. After Mech. Change Cat Converter, he spread some cleaner in to the Throttle. Engine on

See what I have tried before I changed Cat Converter:

1. I have changed Mass Air Flow Sensor. Didn't solve the problem. Put my old sensor back

2. Cleaned EGR valve. Problem was still there

3. Checked Fuel Pump pressure. It was OK

Decided to change Cat Converter. Problem was solved. Now car has so much power. WOW
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Thursday, April 3rd, 2008 AT 11:35 AM
Tiny
TOMMYBONGHITTER
  • MEMBER
  • 5 POSTS
  • 2002 CHEVROLET IMPALA
  • 235,000 MILES
2002 chevy impala making clanking noise after 4 grand rpms and a big loss of gas miles just changed coil packs could it be plugs and wirers or fuel filter
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
You need to verify where the clanking noise is coming from. If it is from the exhaust, it could be the catalytic converter. This should trigger the Malfunction Indicator Light to come on.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
TOMMYBONGHITTER
  • MEMBER
  • 5 POSTS
No it sounds like the front end used to get 25 to 28 miles to gallon now iam getting 14 to 16 miles to a gallon it does seem doggish on take off now too
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Is there any warning indicators illuminated in dash?
You would need to get someone to have a look at it to locate the source of the noise. We can't do this online.
As to the fuel consumption, it might or might not be related to the noise and for a start, have a tune-up for the engine.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
TOMMYBONGHITTER
  • MEMBER
  • 5 POSTS
No warning signs and only makes npise when I step on it I think its the fuel filter or catalitic converter
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Fuel filter shouldn't be making any noises but catalytic converter might. When engine is cold, tap the catalytic converter and note if there are any vibrating noise coming from it.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KWIESMORE
  • MEMBER
  • 4 POSTS
  • 2002 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 90,000 MILES
I have a 2002 Impala 3.8 ltr engine. Runs fine, starts no problem, but no acceleration going up hills or to speed up. Hesitates then tries to speed up. Can barely get up a hill. Took it to a shop, the only code that showed up was the gas cap and a misfire code, probably from gunning it to get up a hill and the check engine light started flashing. The check engine light was on for about a month, we replaced the gas cap, it went off but came back on. The shop reset the codes, so far it hasn't come back on, but still no power. Any ideas? Oh, we did replace the fuel filter. Seemed to help a little.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
TOMMYBONGHITTER
  • MEMBER
  • 5 POSTS
Yes does make noise but doesnt turn red when hot might be going but not pluged will fix and see thank you
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Sounds like a possible cat converter problem. If you can disconnect it from the exhaust manifold and see if you have power. Another think to check is see if you MAF sensor is reading correctly. You can also disconnect that and see if you have full power or not.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
It doesn't necessarily turn red hot when plugged. It would turn red hot when excessive fuel gets to it.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KWIESMORE
  • MEMBER
  • 4 POSTS
Thanks for your reply! I took it to the dealer, yes it was the catalytic converter, and it was covered under the extended EPA law. Runs like new again! The 2001 and 2002 Impalas are covered for 10 yrs/120,000 miles.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
TOMMYBONGHITTER
  • MEMBER
  • 5 POSTS
Thanks was converter runs good now like having power back again
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Glad to know you have the problem fixed.

Have a nice day.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
JWATSON4
  • MEMBER
  • 1 POST
  • 2002 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 65,000 MILES
A month ago this car felt like it didn't have the same power it used to. Starting from stop it feels like it is being held back and I can hear the sound of air flowing. As I accelerate eventually the sound quits and power is restored but by then I'm about at the top end of that gear range and when it shifts I can feel the power loss again. Engine code came up P0404 and I changed the EGR valve hoping to fix it but problem persists.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,749 POSTS
It sounds like a ignition skip to me. When was the last time you gave her a tune up? Pl;ugs and wires usually takes care of the ignition skip. Remove wires at coil and see if there are any rust marks, this is a dead giveaway.
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Saturday, February 23rd, 2019 AT 3:45 PM (Merged)
Tiny
ELUDWIG
  • MEMBER
  • 2 POSTS
  • 2002 CHEVROLET IMPALA
  • 126,000 MILES
I was driving in the mountains of WV when all a once my car started to sputter and I lost power going up the hills. Engine temperature went up slightly. The check engine light did not come on. I took it to an auto zone and had them hook it up to check for codes and nothing came up. Changed the fuel filter and that didn't help.
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Saturday, February 23rd, 2019 AT 3:46 PM (Merged)
Tiny
DAN_K
  • MECHANIC
  • 213 POSTS
A loss of power can be a tricky one to diagnose without further information. When you say "sputter" did it feel as it was mis-firing? I would assume that misfire codes would have been recorded if that's the case. Has the car been well-maintained? When was the last time the car has had a tune-up - with new spark plugs and wires? Does it only happen when going uphill? I think more detective work is going to be required to provide further information. See if you can recreate the driveability condition and pay close attention to the sputtering. Does it buck and***** violently or is it more mild. Pay attention to locations of vibrations to see if it engine or transmission related. I'm apologize for not being able to provide a more specific area of diagnosis, but more information will definitely be necessary. Good luck!
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Saturday, February 23rd, 2019 AT 3:46 PM (Merged)

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