Hello. Thanks for the donation. Much appreciated !
The DTC codes you have are telling you the vehicle is running rich on fuel. Nothing to do with the catalytic conlvertor !. Below is some of the probable causes. But I would be removing and cleaning the MAF sensor first ! Hope this helps. Let me know
41) For Continuous Memory Only DTC P0171, P0172, P0174 Or P0175: Fuel System At Corrected Fuel Trim
All Continuous Memory ignition and misfire DTCs must be serviced prior to servicing any fuel trim DTCs. DTCs P0171, P0172, P0174 and P0175 indicate a concern when adaptive fuel strategy senses a lean or rich condition beyond minimum or maximum calibrated limit. Fuel system DTC identification is as follows:
Bank No. 1
DTCs P0171 (lean), and P0172 (rich).
Bank No. 2
DTCs P0174 (lean), and P0175 (rich).
Possible causes for these faults are:
Excessive fuel pressure, leaking or contaminated fuel injectors, leaking fuel pressure regulator, low fuel pressure or engine running out of fuel or vapory recovery system fault.
Air leaks after MAF sensor, air intake system obstructions, vacuum leaks, PCV system or improperly seated engine oil dipstick.
Leaking gasket, stuck EGR valve or leaking diaphragm or EVR.
Engine oil overfilled, cam timing, cylinder compression or exhaust leaks before or near HO2S.
Inspect engine for obvious defects in specified systems. Repair as necessary.
Thursday, February 5th, 2009 AT 8:09 PM