2002 Chevy Impala acceleration

Tiny
GLENA
  • MEMBER
  • 2002 CHEVROLET IMPALA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 106,000 MILES
Our Impala has really gotten bad gas mileage and does not accerate good now. It has the engine light on. We took it to a dealership and they said it coded EGR valve, massive air flow sensor, catalytic converter and oxygen sensor. We have replaced egr valve and massive air flow sensor, exhaust manifold gasket and transmission filter and fluid. It has done nothing. It still hestiates when accelerating and then surges and also doesn't go up our hill over 30 mph. My husband is a disabled veteran so we are having a hard time trying to find out what is definitely wrong with it. Please give me an ida.
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Thursday, January 31st, 2008 AT 2:59 PM

2 Replies

Tiny
IGGI71
  • MEMBER
Hi. Looks like we have the same problem. Searching this Web site I found info. Hope it will help you see below

Rough acceleration until about 35-40mph

Posted at Tue Jul 11, 2006 5:10 pm
By raks1980, New to the forum
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Hi, can you please advice.
I own 2002 Chevy Impala 3.4L engine, 111,000.00 miles.
My car doesn't accelerate well until about 40 mph, especially when it is going up the hill or from the start in general (it works fine downhill). I have to really press the gas pedal and then when it goes over the 40 mph it works ok.

Check engine light indicates EGR valve, so I put a brand new valve and it still does the same thing.

In the process I discover that when driving without EGR valve connected to the computer my car works fine but it won t go faster than about 65-70mph. After 70 mph when I press the gas pedal it actually decelerates and engine starts heating.

At idle engine works fine but when trying to accelerate you can hear really fast RPMs but it just doesn't deliver power to the wheels?

It also produces roaring noise even if I press the gas pedal to the max, doesn't react to the until it passes 30-40 mph.

Please help, Max A.

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Posted at Mon Jul 17, 2006 11:37 am
By raks1980, New to the forum
(10) Give Feedback | Votes: 0

1. The problem was my clogged catalytic converter ($275 in mieneken).

Due to the fact that it was clogged the upper block/portion of the engine and somehow spark plugs had heavy carbon deposit.

2. Emission Flush ($180)
3. Spark pugs and wires ($170)

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Friday, February 22nd, 2008 AT 7:38 PM
Tiny
IGGI71
  • MEMBER
Hi again. Info below I found in one of the Web sites

Why do converters go bad?
There are two ways a converter can fail, it can become clogged or it can be poisoned.
When catalytic converters fail they normally clog up with debris and block the flow of exhaust gas from getting out of the system. This will cause tremendous performance problems. In extreme cases it will prevent the vehicle from starting at all. Most of the time it just limits engine performance by choking the flow through the engine. So how do you check a catalytic converter without removing it from the car? Sometimes an indication that a converter is clogged is that you don't go any faster when you push the gas pedal down. In addition there usually is a noticeable drop in fuel economy associated with a clogged catalytic converter. A totally clogged converter will cause the engine to die because of the increased backpressure.
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Friday, February 22nd, 2008 AT 7:46 PM

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