after repairs I'm getting a new code PO172

Asked by Valerie Aug 24, 2020 at 07:27 AM about the 2004 Chevrolet Trailblazer LS 4WD

Question type: Maintenance & Repair

I have replaced the air injection valve,both oxygen sensors,spark plugs,cleaned the throttle body and replaced the gasket,replaced the small vacuum hose to the air box. now it is giving me a code of PO172 the engine is racing at a high throttle then goes back to normal then high throttle again any help would be appreciated

1 Answer

11,245

P0172 popped up AFTER you changed those things? A few things to know here. Our 4.2 engine loves AC Delco spark plugs, 41-103. Also, some brands of oxygen sensors can be touchy, and not be within the parameters of GM if it's not AC Delco or Delphi. Bosch 02 sensors are the worst. Since, 04 doesn't have a MAF, try cleaning your MAP sensor. Make sure all of your connections from the airbox and throttle body are good air tight. Further than this, you may have to do a fuel pressure test at the rail. If this code popped up only after your recent work, it's something you did, and easily fixable. Triple check all your work.

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