Mechanics

CHEVY LOSS OF POWER

2003 Chevrolet Impala

Engine Performance problem
2003 Chevy Impala 6 cyl Front Wheel Drive Automatic 157000 miles

It just started 3 days ago and getting worse. OBD2 reads code P0420. From 20 to 50 mph it seems to have a loss of power when I step on the gas. Do you suggest with code given the catalyst converter needs to be replaced?
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Skenney37
November 13, 2008.



Yep; the code and the lack of power at higher speed are typical of a plugged converter resulting in excessive back pressure.
Check exhaust backpressure to makes sure.
In your case it went bad probably because it had 157,000 miles on it, however a bad converter is sometime the result of another problem such as worn exhaust valve, leaky head gasket, cracked cylinder, bad coolant sensor, etc.

Tiny
RenaudTN
Nov 14, 2008.
I have a 2003 chevy impala no code are on but it loss power when I step on the gas what can be the problem.I tried this egr valve mass air flow sensor tps coils ignition control module what can it be please need help
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Tiny
Hartleykid
Sep 13, 2011.
Check the fuel pressure. There is a test port on the fuel rail. Auto Zone or Advance Auto has fuel pressure test gauges they will loan out if you give them a deposit.


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