Here is a post from a site that I found.
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My engine is knocking and ping’ing what can I do?
http://www.automotiveforums.com/vbulletin/showthread.php?t=178212
http://www.automotiveforums.com/vbulletin/showthread.php?t=153083&highlight=ion
If you have a 2000-2004 Isuzu, make sure you only use Denso K16PR-P11 spark plugs. Check the link below to buy them for 6.80/plug (note the dealer charges about 17/plug)
http://www.sparkplugs.com/results_app.asp?AAIA=1363272&mfid=3
The 2000-2004 engines have the GM/delphi "ion sensing" ignition system where the spark plugs are used as a sensor (when they are not firing) to measure the electrical resistance of the gasses in the combustion chamber. Other plugs may cause the ECU to register a code (misfire code: P1340). Also, it has been noted that some 00 trucks came with champion plugs from the factory, which cause knocking, due to to ion sense coils.
If you have 1998-1999, the suggested plugs are NGK or Denso or Champion double platinum plugs.
A dirty EGR port may cause knocking. Knocking also, may be caused by carbon build-up in the combustion chamber. Adding one 20oz bottle of Chevron Techron Concentrate® every 3k, will help to keep the combustion chamber and fuel injectors clean. Also Sea Foam is another excellent product to use (it can be added to the gas and the oil).
Finally keep that PCV valve clean! Either replace it once a year, or pull it every 6 months or so and spray it out with some carb cleaner.
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Of course this is for isuzu rodeos, but if you don't already know Honda Passports are the same SUV, just with different name plates.
I have not solved my problem quite yet... My Passport already has Denso plugs, so I will put new ones in, and I might try to get the newest ECU configuration from the dealer, which was a recommendation from one of the automotiveforum threads.
Will post an update as soon as I fix my problem.
