Mitsubishi Repair Problems? Ask a Mechanic for Answers ASAP
What year is this Montero? There is a software update for erroneous P0125 that may apply. Likewise, has the fuel pressure been checked cranking/running/and key off to make sure there is no fuel pressure regulator issue (very common for P017x codes)? How about vacuum leak checks?
That's good if you have the software update already, so that rules that out anyway.You could still go either way with the fuel trims.. in fact being at idle is less reliable in general than while driving anyway (often even zeroing out in some cases). Under load is when you get a most reliable reading.With the engine running, if you spray brake parts cleaner around the intake manifold sealing areas does the engine flare/react at all?