WHAT TO DO TO FIX PO300 CODE

  • Tiny
  • GARY KRUEGER
  • 1999 GMC Jimmy

My 1999 jimmy is giving a po 300 code it runs very rough. Has new cap and rotor, the plugs and wires are less than a year old. Used a cigar to blow smoke into intake to check for vacuum leak found none. Freeze frame data showed stft bank one 13.5%ltft bank one 0% stft bank 2 12.8% ltft bank 2 0% what would my next option be and how would I go about it thanks for response gary

Wednesday, September 26th, 2012 AT 1:34 AM

2 Answers

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,555 posts

First, do a compression test to make sure the motor is good.

The 300 is a random missfire. It could be an injector but before we go there. Do the test

Roy

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Wednesday, September 26th, 2012 AT 1:44 AM
  • Tiny
  • GARY KRUEGER
  • Member

THE COMPRESSION TEST CHECKED OUT GOOD ON ALL 6 CYLINDERS

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Thursday, September 27th, 2012 AT 2:29 AM

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