2003 Impala 3400 V-6.

How to perform an exhaust back-pressure test.

Engine Performance Diagnostics chapter 1 pages 8 & 28

symptoms 50

  • very low power (could not accelerate past 30 mph)
  • pinging and detonation

fix 50

  • replace the restricted catalytic converter

test shown enh 50

  • O2 sensor reading at wide open throttle (shows fuel delivery and direction for our low power complaint)
  • exhaust backpressure test using a gauge installed in the upstream O2 port

Tools used

  • scan tool
  • exhaust back-pressure gauge

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(Chapter 1) Misfire ID, Compression Test, Vacuum Leaks, Fuel Trim, Head Gasket, Restricted Exhaust, Low Power, DVOM

Related videos:

How to test for a restricted exhaust using the DPFE sensor on a Ford:


How to test for a plugged exhaust (picoscope & psi transducer):


Exhaust Backpressure Testing (known bad compared to known good):


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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

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