2004 Toyota Corolla P0300-0304 P0171

2004 TOYOTA COROLLA
67,000 MILES • 4 CYL • 2WD • AUTOMATIC
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CTRAINCHEN
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  • 1 POST
Hi, the scanned OBD II code shows: P0300, P0302, P303, P304, P0171. The abnormal behavior is: when engine is idling, I feel the shake of the car body (probably caused by engine) in back and forth direction, especially when engine becomes warm. What could be the root cause of this error? Thanks.
Sep 12, 2009 at 10:41 PM
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MMPRINCE4000
  • AUTOMOTIVE REPAIR CONTRIBUTOR
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The P030x errors are misfires, so either the plugs, and/or coils. Also possible a fuel pressure issue.
The P0171 error is a lean condition.

First have fuel pressure measured with mechanical gauge, if OK, then replace plugs, use only Denso or NGK Iridium. If problem persists, have the coils tested.

Also check the battery ground to block, make sure it is clean and tight.

It is also possible that you have a clogged convertor causing all the misfires. You may want to check that first.
Sep 14, 2009 at 9:09 AM